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termination of the glacier. This inference was suggested by the seeks in the past to discover the germ of the present. He tells consideration that pressure and erosion would be least when the us that we cannot hope to understand the complicated structure glacier was flowing upon a steep slope, while at the base of and relations of a society like ours without a full appreciation such a slope where the valley flattened out, the ice would tend of all that has gone before. And so it is in the case of geolo. to heap up, as it were, and produce the maximum amount of gical history. The present has grown out of the past, and bears pressure and erosion. Thereafter, as the ice continued to flow myriad marks of its origin, which would either be unobserved down its valley, it would become thinner and thinner until it or remain totally meaningless to us, were the past a sealed book. reached its termination-and pressure and erosion would diminish No student of physical geography, or of zoology and botany, with the gradual attenuation of the glacier. Such conditions, therefore can afford to neglect the study of geology, if his desire after some time, would necessarily result in the formation of be to acquire a philosophical comprehension of the bearings of elongated rock-basins, sloping in gradually from either end, and those sciences. For it is geology which reveals to us the birth attaining their greatest depth at some point above a line drawn and evolution of our lands and seas-which enables us to follow midway between the upper and lower ends of a hollow. There the succession of life upon the globe, and to supply inany of the are many other details connected with this most ingenious theory missing links in that chain, which, as we believe, unites the which I cannot touch upon at present. It will be sufficient to beginning of life in the far distant past with its latest and highest say that the observed facts receive from it a simple and satisfac expression in man. By its aid we track out the many wander tory explanation. Like all other well-based theories, it has ings of living genera and species which have resulted in the been fruitful in accounting for many other phenomena, a study present distribution of plants and animals. But for geology, of which has developed it in various directions, and enabled us indeed, that distribution would be for the most part inexplicable. to understand certain appearances which the theory as at first How, for example, could we account for the often widely sepapropounded seemed hardly adequate to explain. As a proof of rated colonies of arctic-alpine plants which occur upon the the soundness of Ramsay's conclusion that ice is capable of ex mountains of Middle and Southern Europe? How could these cavating large rock-basins, I may mention that his theory has led plants possibly have been transferred from their head-quarters in to the prediction of facts which were not previously known to the far north to the hills of Britain, and Middle Germany, to geologists. He had pointed to the occurrence, in many of the the Alps and the Pyrenees? Not the most prolonged and labosea-lochs of Western Scotland, of deep rock-bound bollows, rious study of the botanist could ever have solved the problem. which he concluded must have been formed by great valley But we learn from the geologist that the apparent anomalous glaciers in the same way as the hollows occupied by fresh-water distribution of the flora in question is quite what his study of lakes in this and other similarly glaciated countries. Some years the rocks would have led him to expect. He now, indeed, later, having discovered that the Outer Hebrides had been appeals to the occurrence of those curious colonies of arcticglaciated across from side to side by a mer de glace flowing out alpine plants as an additional proof in support of his view that wards from the mainland, and having been satisfied as to the during a comparatively recent period our continent experienced truth of the glacial-erosion theory, I was led by it to suppose a climate of more than arctic severity. He tells us that at that that deep rock-basins ought to occur upon the floor of the sea time the reindeer, the glatton, the arctic fox, the musk ox, and along the inner margin of most of our Western Islands. This other arctic animals migrated south into France, while a Scandiexpectation was suggested by the simple consideration that those navian flora clothed the low grounds of Middle Europe. By islands, presenting, as they for the most part do, a steep and and by, when the arctic rigour of the climate began to give way, abrupt face to the mainland, must have formed powerful ob the northern species of plants and animals slowly returned to structions to the out-flow of the mer de glace in the direction of the high latitudes from which they had been driven. Many the Atlantic. This being so, great erosion, I inferred, must plants, however, would meet with similar conditions by ascend. have ensued in front of those islands. The lower part of the ing the various mountains that lay in the path of retreat, and mor de glace wbich overflowed them would be forced down upon there they would continue to flourish long after every trace of the bed of the sea by the ice continually advancing from behind, an arctic-alpine flora had vanished from the low ground. This and compelled to flow as an under-current along the inner explanation fully meets the requirements of the case. It leaves margin of the islands, until it circumvented the obstruction, and none of the facts unaccounted for, but is in perfect harmony with resumed the same direction as the upper portion of the mer de all. But as if to make assurance doubly sure, Dr. Nathorst, a glace, A subsequent careful examination of the Admiralty's well-known Swedish geologist, recently made a search in the Charts of our western seas, which afford a graphic delineation low grounds of Europe for the remains of the arctic-alpine flora, of the configuration cf the sea-bottom, proved that the and succeeded in discovering these in many places. He de. deduction from Ramsay's theory was perfectly correct. tected leaves of the arctic willow and several other characteristic Were that sea bed to be elevated for a few hundred feet, so northern species in the glacial and post-glacial deposits of a to run off the water, and unite the islands to themselves Southern Sweden, Denmark, England, Germany, and Switzerand the mainland, we should find the surface of the new land, and thus supplied the one link which might have been born land plentifully diversfied with lakes-all occupying the sidered necessary to complete a chain of evidence already positions wbich a study of the glaciation of the mainland and almost perfect. islands would have led us to expect. Among the most consider From this and many similar instance that might be given we able would be a chain of deep lakes extending along the inner learn that the reconstruction of the past out of its own ruins is margin of the Outer Hebrides, while many similar sheets of not mere guess-work and hypothesis. The geologist cannot water would appear in front of those islands of the Inner Group only demonstrate that certain events have taken place, but he that face the deep fiords of our western shores.
can assure us of the order in which they succeeded one after the The few examples now given of geological methods of inquiry other, during ages incalculably more remote than any with which may suffice to show that the process of reading and interpreting historians have to deal. The written records out of which are the past in the light of the present necessitates not only accurate constructed the early history of a people cannot always be observation, but an extensive acquaintance with the mode in depended upon-allowance must be made for the influences that which the operations of Nature are carried on. They also serve may have swayed the chroniclers, and these are either unknown to show that just as our knowledge of the past increases, so our or can only be guessed at. It follows therefore that events are insight into the present becomes more and more extended. For seldom presented to us in a consecutive history exactly as they if it be true that the present is the key to the past. it is not less occurred. They are always more or less coloured, and that certain that without that unfolding of the past which a study of colouring often depends fully as much upon the idiosyncrasies of the rocks has enabled us to accomplish, we should not only miss the modern compiler as upon those of the contemporaneous the meaning of much that we see going on around us, but we recorder. The geologist has at least this advantage over the should also remair in nearly complete ignorance of all that is investigator of human history, that his records, however frag. taking place within the crust of our globe. Thus, although our mentary they may be, tell nothing more and nothing less than science may be correctly defined as an inquiry into the develop the truth. Any errors that arise must be due either to insuffiment of the earth's crust and of the faunas and floras which cient observation or bad reasoning, or to both, while the prohave successively clothed and peopled its surface-yet that defi gress of research and the penetrating criticism which every novel nition is somewhat incomplete. For, as we have seen, this in view undergoes must sooner or later discover where the truth quiry into the past helps us to understand existing conditions lies. In this way the history of our globe is being gradually better than we should otherwise do. In this respect it is with reconstructed-to an extent, indeed, that the earlier cultivators geology as with human history. The philosophical historian of the science could not have believed possible. But although
many blanks in the rccords have been filled up, and our know. our preconceived notions do not lead us to colour the evidence ledge will doubtless be yet greatly increased, it must nevertheless or to blind us to facts that tell against our views. Every theory be admitted that this knowledge must always bear but a very should be considered provisional until its truth has been fully small proportion to our ignorance. In this, however, there is demonstrated by an overwhelming array of testimony in its nothing to discourage us, as we may be quite sure that the work
favour. Until this consummation is arrived at we must be conremaining to be done will far exceed all the energies of many stantly testing its truth, and be ready to abandon it at once generations to accomplish.
whenever the evidence shows it to be erroneous. The failure of It is sometimes objected to Geology that its results are not one theory after another need not disconcert or discourage us ; always so exact as those which are obtained by an experimental for each failure, by reducing the number of possible explanascience like chemistry. We are reproached with the fact that tions, must necessarily bring us nearer to our goal—the truth. I our theoretical conceptions undergo frequent modification, and cannot but deem it a strong point in favour of geology as a branch are even often abandoned, to be succeeded by others wbich, of education that it not only cultivates the faculty of clear and after flourishing for a time, are in like manner overturned and continuous observation, but abounds in unsolved problems thrown aside. But the same reproach, if it be one, might be which are ever suggesting new ideas and thus stimulating that brought against other sciences. 'Each advancing science has imagination which is one of the noblest gifts of our race. It is its problems and speculations. And we cannot often feel no reproach that the progress of our science is marked by the assured that the solution now given of those problems will in all modification and abandonment of numerous hypotheses and cases stand the test of time. Our theoretical conceptions of the theories. On the contrary, these afford a measure of the rate ultimate constitution of matter, for example, bave within com. at which geology advandes—just as this last yields the strongest paratively few years undergone considerable change, and yet no testimony to the good results that accrue from having some one values chemistry the less. Let our theories be what they provisional view by which to direct the course of our observamay, they do not and cannot overturn the results obtained by tions. verified observation and often repeated and varied experiment. It It is unavoidable that in the onward march of a science the remains for ever true that water is composed of oxygen and hy. facts become at last so numerous as to task all the energies of its drogen, let our views of the atomic theory change as they may. votaries to keep abreast of their time. When a beginner first And so it is not less certain that strata of conglomerate and sand. surveys the wide field embraced by geological inquiry, he may stone containing marine or fresh-water fossils are of aqueous not unnaturally experience a feeling akin to despair. How is it origin, however much our theoretical conce tions may vary as to possible, he may think, that I can master all these manifold the uniformity in degree between the past and present opera details—how can I test the truth of all those numerous inferences tions of Nature. It is true we did not see the conglomerate and conclusions--and yet have sufficient leisure and energy left and sandstone in process of formation, but we know by obser to undertake original observation ? Well, no one can hope to vation that these rocks exactly resemble deposits of gravel and
advance the science in all its departments. When we reflect sand which are now being accumulated in water. Nature in that in order to obtain a complete comprehension and mastery this case makes the experiment for us, whereas the chemist has of the existing condition of things we should require to be to do this for himself. The latter, having well ascertained by adepts in physics, mechanics, chemistry, and every branch of varied experiments the composition of certain samples of water, natural science, it is obvious that such a perfect knowledge is henceforth c ncluces that all water is made up of the same two beyond attainment. It is needless, therefore, that we should gases in definite proportions. But this conclusion of his is just strive to become “admirable Crichtons” in this nineteenth as much an assumption as the inference of the geologist that century, and no beginner need be discouraged by the greatness strata containing marine or freshwater fossils are aqueous accu of the science which he desires to cultivate. It is only by divimulations. It is when we come to the larger generalisations of sion of labour that so much has been accomplished ; and the our science that we are more likely to go astray. The problems results are now so systematised that it is quite possible for any we have to solve demand not only an accurate knowledge of intelligent inquirer to gain a thorough comprehension of the widely scattered phenomena, but a ready command of logical principles of the science. But this it is absolutely necessary analysis. The facts may be sufficiently abundant, but if we to acquire, and the student, therefore, should at first devote all reason badly we of course miss their meaning. Or, on the other his energies to learn as much as he can of those principles and hand, the evidence may be more or less imperfect. There are their application. When he has progressed so far, he is then blanks which we fill up with conjecture—which can do no harm ready to set out as an explorer in the well-assured hope that if so long as we do not treat our conjectures as if they were facts. he be true to the logical methods which have hitherto succeeded But when the gap; in the evidence are numerous, each theoriser so well, he will not fail to reap his reward in the discovery of will fill them up after his own fashion, and very various results new truths. But to secure success we must be content to be will thus be obtained. Even in cases of this kind, however, a specialists. In other words, we must concentrate our energies rigorous application of logical analysis will enable us to detect upon some particular lines of inquiry, and do our utmost to the fallacies which may underlie all the competing theories ; and work these out in all their details. At the same time we should we are thus prepared to frame a new explanation for ourselves, make a great mistake if we aid not always keep in mind the and to :et about searching for additional facts to prove or dis broader bearings of our science, and endeavour to maintain as prove our notions. In all such investigations it is obviou-ly the wide a knowledge as we can of all its branches. Each of these, duty of a careful observer and theoriser to see well to his pre we may be sure, has something to tell which will aid us in our mises-to be absolutely sure as to his facts, and to distinguish own special inquiries. We cannot, therefore, afford to neglect clearly between what is substantial knowledge, and what is the side-lights which are thrown upon our path from the lamps mere conjecture. He will thus be in a position to judge whether of others who are working in adjacent fields. One cannot help his conciusions are based on a solid foundation or not. In a thinking that many specialists would have given us more and science of observation like geology, theory is necessarily often better work if they had no: allowed themselves to be cramped in advance of the facts. Some, indeed, have insisted that all and narrowed by continuing too long in one rut or groove. They conjectural explanations are quite a mistake; that it would be dig so deep that they get into a hole out of which it is somebetter to avoid theorising altogether, and to wait patiently until times difficult to climb, and thus not infrequently the work the chain of evidence had completed itself. I am afraid that, being done by fellow-labourers, escapes them, and they miss the were it possible to follow this advice, we might often have to suggestions which a knowledge of that work might otherwise wait a very long time. After all, a heap of bricks is only a have yielded them. potential house: it will not grow up into walls without the aid of I have said nothing as to the practical applications of our architect and builder. Discoveries in science have no doubt science—that branch of our subject which is termed economic been inade occasionally by isolated and haphazard observations; geology-not because I consider it the less important, but but that is exceptional, and we should not be where we are now because its value is generally recognised and need not now be bad the examination of Nature been always conducted after such insisted upon. Many, I do not doubt, enter upon their a fashion. If additional evidence be required, we must first geological studies with a distinct view of obtaining from the have some notion where to look for it. In other words, it is science such help as it can afford them in the practical pursuits essential to progress that we should have preconceived opinions of life. To such inquirers it will be my pleasure not less or theories, which enable us to arrange the facts we already pos than my duty to give every assistance that is in my power. sess, and to point out the directions in which further evidence But I would point out to them that there is no short cut to the may be looked for.
We cannot be too careful, however, that attainment of the knowledge they are in quest of. The study
of economic geology cannot be separated from that of the recog. viduals, or to committee , specific inquiries, to be reported upon nised principles and methods of inquiry which must be followed to the different sections at subsequent ineetings; whereas the by ibe scientific investigator. On the contrary, the more tho- | Society of Arts, with its 3,450 permanent members, its ninety: roughly we devote ourselves to the prosecution of geology for five associated societies, spread throughout the length and breadth its own sake the better able shall we be to appreciate its of the country, its permanent building, its well-conducted economic bearings.
Fournal, its almost daily meetings and lectures, extending over In beginning the duties of this Chair, if I enjoy certain ad six months of the year, possesses exceptionally favourable opporvantages over my predecessor, I also at the same time labour tunities of following up questions of industrial progress to the under considerable disadvantages. The Class Museum formed point of their practical accomplishment. In glancing back upon by bim, and the other appliances and aids to teaching which he its history during the 128 years of its existence, we discover that laboriously gathered together have been generously handed over tha Society of Arts was the first institution to introduce science to the Chair-and this, I need not say, has greatly smoothed my into the indu trial arts; it was through the Society of Arts and path. But, on the other hand, he has left behind him a reputa- its illustrious Past President, the late Prince Consort, that the tion which must bear hard upon me. He has not only sustained first Universal Exhibition was proposed, and brought to a suc but increased the fame of what has been termed the Scottish cessful i-sue in 1851; and it is due to the same Society, supported School of Geology, and I feel that it will task all my energies on all important occa-ions by its actual President, the Prince of to emulate the high standard he maintained as a teacher. It is Wales, that so many important changes in our educational and not without diffidence, therefore, that I commence this course ; industrial institutions have been inaugurated, too numerous to be but my hope is that the love of science, which has bitherto referred to specifically on the present occasion. carried me over many years of a laborious occupation, may at Amongst the practical questions that now chiefly occupy public least succeed in warming and sustaining the enthusiasm of those attention are those of Electric Lighting, and of the transmission who come here to study with me what geology has to reveal of force hy electricity. These together form a subject which has concerning the pa: t and present.
occupied my attention and that of my brothers för a great num
ber of years, and upon which I may consequently be expected to A METHOD FOR OBSERVING ARTIFICIAL I could deal only with some purely scientific considerations in
dwell on the present occasion, considering that at Southampton TRANSITSI
volved in this important subject. I need hardly remind you that As many astronomers who intend to observe the coming electric lighting, viewed as a physical experiment, has been transit of Venus have neither the time nor means for
known to us since the early part of the present century, and that making the necessary arrangements to practice or artificial
many attempts have, from time to time, been made to promote transits, the sim, le method here prɔposed may be advanta:
its application. Two principal difficulties have stood in the way geously employed. Instead of observing an artificial sun and
of its practical introduction, viz , the great cost of producing an planet placed at a distance of several thousand feet from the electric current so long as chemical means had to be resorted to, observer, I would suggest that the real suo be observed, and the
and the mechanical difficulty of constructing electric lamps planet Venus to be represented by a circular disk, held, in the capable of sustaining, with steadiness, prolonged effects. The common focus of the objective and eye-pieee, by means of a
dynamo-machine, which enables us to convert mechanical into narrow metallic arm fastened to the eye-piece.
electrical force, purely and simply, has very effectually disposed The relative motion of the sun and Veus can then be pru
of the for ner difficulty, inasmuch as a properly conceived and duced by so adjusting the rate of the driving clock that the
well constructed machine of this character converts more than angular motion of the telescope on the hour-axis shall exceed the ninety per cent. of the mechanical force imparted to it into elecdiurnal motion of the sun hy seventeen seconds of time per tricity, ninety per cent, again of which may be re-converted into hour. In this way, as the atmospheric disturbances of the sun's
mechanical force at a moderate distance. The margin of loss, limb are real, a near aprroach to the phenomena observed during therefore, does not exceed twenty, per cent., exclu ting purely an actual transit will result. If a light-shade glass is employed,
mechanical losses, and this is quite capable of being further the opaque disk will be seen before it comes into apparent con
reduced to some extent by improved modes of construction; but tact with the sun. The observer can, however, by an exercise
it results from these figures that no great step in advance can be of the will, confine his whole attention to the sun's limb.
looked for in this direction. The dynamo-machine presents the By using a heavier shade-glass the disk will not be seen until it
great advantage of simplicity over steam or other power-transis projected against the image of the sun. The angular diameter mitting engines; it has but one working part, namely, a shaft of Venus at the time of transit being about 65", the diameter of which, revolving in a pair of bearings, carries a coil or coils of the opaque disk should be 65·lósin I" = 0'00031·l, 7 being the
wire admitting of perfect balancing. Frictional resistance is focal length of the telescope used. The position angle of the
thus reduced to an absolute minimum, and no allowance has to point of contact can be changed at will by simply moving the
be made for los; by condensation, or badly fitting pistons, telescope in declination.
stuffing boxes, or valves, or for the jerking action due to osclllating weights. The materials composing the machine, namely,
soft iron and copper wire, undergo no deterioration or change by ELECTRIC LIGHTING, THE TRANSMISSION continuous working, and ihe depreciation of value is therefore a OF FORCE BY ELECTRICITY 2
minimum, except where currents of exceptionally high potential
are used, which appear to render the copper wire brittle. HAVING received the honour of being elected Chairman of the Council of the Society of Arts for the ensuing year,
The essential points to be attended to in the conception of the the duty devolves upon me of opening the coming Session with
dynamo-machine, are the prevention of induced currrents in the some introductory remarks. Only a few months have elapsed
iron, and the placing of the wire in such position as to make
the whole of it effective for the production of outward current. since I was called upon to deliver a pre-idential addre;s to the British Association at Southampton, and it may be reasonably
These principles, which have been clearly established by the supposed that I then exhausted my stock of accumulated thought
labours of comparative few workers in applied science, admit of and observation regarding the present development of science, forms, for each of which may be claimed some real or imaginary
being carried out in an almost infinite variety of constructive both abstract and applied ; that, in fact, I come before you, to
merits regarding questions of convenience or cost of production. use a popular phrase, pretty well pumped dry. And yet so large is the field of modern science and industry, that, notwithstanding
For many years after the principles involved in the construc
tion dynamo-machines had been made known, little general the good opportunity given me at Southampton, I could th-re do
interest was manifested in their favour, and few were the forms only scanty justice to comparatively few of the branches of
of construction offered for public use. The essential features modern progress, and had to curtail, or entirely omit, reference
involved in the dynamo-machine, the Siemens armature (1856), t others, upon which I should otherwise have wished to dwell.
the Pacinotti ring (1861), and the self-exciting principle (1867), There is this essential difference between the British Association and the Society of Arts, that the former can only take an annual
were published by their authors for the pure scientific interest
attached to the r, without being made subject matter of letters survey of the progress of science, and must then confide to indi
patent, which circumstance appears to have had the contrary * By Prof. J. M. Schaeberle, Ann Arbor, Michigan. From the American effect of what might have been expected, in that it has retarded Journal of Science. Address by Dr. C. W. Siemens, F.R.S., Chairman of the Society of
the introduction of this class of electrical machine, because no Arts, November 15.
person or firm had a sufficient commercial interest to undertake
the large expenditure which must necessarily be incurred in for its prolongation from time to time, or by a provisional order reducing a first conception into a practical shape. Great credit which would, in that case, be obtained by joint application of the is due to Monsieur Gramme for taking the initiative in the contractor and the local authority. At the time of expiration of practical introduction of dynamo-machines embodying those the provisional order, a pre-emption of purchase is accorded to the principles, but when five years ago I ventured to predict for the local authority, against which it has been objected with much dynamo-electric current a great practical future, as a means of force by so competent an authority as Sir Frederick Bram» ell, transmitting power to a distance, those views were still looked that the conditions of purchase laid down are not such as fairly upon as more or less chimerical. A few striking examples of to remunerate the contracting companies for their expenditure what could be practically effected by the dynamo-electric current and risk, and that the power of purchase would inevitably such as the illumination of the Place de l’Opera, Paris, the induce the parochial bodies to become mere trading associations. occasional exhibition of powerful arc lights, and teir adoption But while admitting the undesirability of such a consummation, for military and lighthouse purposes, but especially the gradual | I cannot help thinking that it was necessary to put some ter.in to accomplishment of the much desired lamp by incandescence in contracts entered into with speculative bodies at a time when the vacuum, gave rise to a somewhat sudden reversion of public true value of electric energy, and the best conditions under which feeling ; and you may remember the scare at the Stock Exchange it should he applied, are still very imperfectly understood. The affecting the value of gas shares, which ensued in 1878, when supply of electric energy, particularly in its application to transthe accomplishment of the sub-division of the electric light by mission of power, is a matter simply of commercial demand and incandescent wire was first announced, somewhat prematurely, supply, which need not partake of the character of a large through the Atlantic cable.
monopoly similar to gas and water supply, and which may thereFrom this time forward electric lighting has been attracting fore be safely left in the hands of individuals, or of local more and more public attention, until the brilliant displays at associations, subject to a certain control for the protection of the exhibition of Paris, and at the Crystal Palace last year, public interests. At the termination of the period of the proserved to excite public interest, to an extraordinary degree. vi-ional order, the contract may be renewed upon such terms and New companies for the purpose of introducing electric light and conditions as may at that time appear ju t and reasonable to power have been announced almost daily, whose claims to Parliament, under whose authority the Board of Trade will be public attention as investments were based in some cases upon empowered to effect such renewal. only very slight modifications of well-known forms of dynamo- Complaints appear almost daily in the public papers to the machines, of arc regulators, or of incandescent carbon lights, effect that townships refuse their assent to applications by electric the merits of wbich rested rather upon anticipations than upon light companies for provisional orders; but it may be surmised any scientific or practical proof. These arrangements were sup- that many of these applications are of a more or less speculative posed to be of such superlative merit that gas and other illumi- character, the object being to secure monopolies for eventual use or nants must soon be matters simply of history, and hence arose sale, under which circumstances the authorities are clearly justified great speculative excitement. It should be borne in mind, in withholding their a sent; and no licenses or provisional orders however, that any great technical advance is necessarily the should, indeed, be granted, I consider, unless the applicants can work of time and serious labour, and that when accomplished, give assurance of being able and willing to carry out the work it is generally found that so far from injuring existing industries, within a reasonable time. But there are technical que:tions init calls additional ones into existence, to supply new demands, volved which are not yet sufficiently well understood to admit of and thus gives rise to an increase in the sum total of our re- immediate operations upon a large scale. It is, therefore, reasonable to expect that side by side Attention has been very properly called
the great with the introduction of the new illuminant, gas lighting will go divergence in the opinions expressed by scientific men on improving and extending, although the advantage of electric garding the area that each lighting district should comprise, light for many applications, such as the lighting of public halls the capital required to light such an area, and the amount of and warehouses, of our drawing rooms and dining-rooms, our
electric tension that should be allowed in the conductors. In the passenger steamers, our docks and harbours, are so evident, that case of gas supply, the works are necessarily situated in the outits advent may be looked upon as a matter of certainty.
skirts of the town, on account of the nuisance this manufacture Our Legislature has not been slow in recognising the import- occasions to the immediate neighbourbood; and, therefore, gas ance of the new illuminant. In 1879, a Select Committee in supply must rarge over a large area. It w uld be possible, no the House of Commons instituted a careful inquiry into its doubt, to deal with electricity on a similar basis, to establi- h nature and probable cost, with a view to legislation, and the electrical mains in the shape of copper rods of great thickness, conclusions at which they arrived were, I con-ider, the best that with branches diverging from it in all directions ; but the could have been laid down. They advised that applications question to be considered is, whether such an imitative curse is should be encouraged tentatively by the granting of permissive desirable on account either of relative expense or of facility of Bills, and this policy has given rise to the Electric Lighting working. My own opinion, based upon considerable practical Bill, 1882, promoted by Mr. Chamberlain, the President of the experience and thought devoted to the : ubject, is decidedly adBoard of Trade, regarding which much controversy has arisen. verse to such a plan. In my evidence before the Parliamentary It could, indeed, hardly be expected that any act of legislation Committee, I limited the desirable area of an electric district upon this subject could give univer: al satisfaction, because while in densely populated towns to a quarter of a square mile, and there are many believers in gas who would gladly oppose any e timated the cost of the necessary establishment of engines, mea-ure likely to favour the progress of the rival illuminant, and dynamo-machines, and conductors, at 100,0col, while other others who wish to see it monopolised, either by local authorities, witnesses held that areas from one to four quare miles or by large financial corporations, there are others again who could be worked advantageously from one centre, and at a cost would throw the door: open so wide as to enable almost all not exceeding materially the figure I had given. These discrepcomers to interfere with the public thoroughfares, foi the estab- ancies do not necessarily imply wide differences in the estimated lishment of conducting wires, without let or hindrance.
cost of each machine or electric light, inasmuch as such estiThe law as now established takes, I consider, a medium cour:e mates are necessarily based upon various assumptions regarding between these diverging opinions, and, if properly interpreted, the numher of hou és and of public buildings comprised in such will protect, I believe, all legitimate interests, without impeding a district, and the amount of light to be apportioned to eacb, the healthy growth of establishments for the distribution of but I still maintain my preference for small districts. electric energy for lighting and for the transmission of power. By way of illustration, let us take the parish of St. James's, Any firm or lighting company may, by application to the local near at hand, a district not more densely populated than other authorities, obtain leave to place electric conductors below public equal areas within the metropolis, althongh comprising, perhaps, thoroughfares, subject to such conditions as may be mutually agreed a greater number of public buildings. Its population, according upon, the terms of such license being limited to seven years; or an to the preliminary report of the census taken on the 4th April, application may be made to the Board of Trade for a provisional | 1881, was 29,865, it contains 3,018 inhabited houses, and its order to the same effect, which, when sanctioned by Parliament, area is 784,000 square yards, or slightly above a quarter of a secures a right of cccupation for twenty-one year-, The license offers the advantage of cheapness, and may be regarded as a To light a comfortable house of moderate dimensions in all its purely tentative measure, to enable the firm or company to prove parts, to the exclusion of gas, oil, or candles, would require the value of tbeir plant. If this is fairly established, the license about ico incandescent lights of from 15 to 18-candle power would in all probability be affrmed, either by an 'engagement each, that being, for instance, the number of Swan lights em
ployed by Sir William Thomson in lighting his house at taken into account; first, the charge for interest and depreciaGlasgow University. Eleven-horse power would be required to tion on the original cost of a unit length of the conductor; and, excite this number of incandescent lights, and at this rate the secondly, the cost of the electrical energy lost through the resisparish of St. James's would require 3,018 X II = 33,200-horse tance of a unit of length. The sum of these two, which may rower to work it. It may be fairly ohjected, however, that be regarded as the cost of conveyance of electricity, is clearly there are many houses in the parish much below the standard least, as Sir William Thomson pointed out some time ago, here referred to, but on the other hand, there are 6co of them when the two components are equal. This, then, is the princiwith shops on the ground floor, involving larger requirements. ple on which the size of a conductor should be determined. Nor does this estimate provide for the large consumption of From the experience of large installations, I consider that electric energy that would take place in lighting the eleven electricity can, roughly speaking, be produced in London at a churches, eighteen club-houses, nine concert halls, three cost of about one shilling per 10,000 Ampère-Volts or Watts theatres, besides numerous hotels, restaurants, and lecture halls. (746 Watts being equal to one horse-power) for an hour. Hence, A theatre of moderate dimensions, such as the Savoy Theatre, assuming that each set of four incandescent lamps in series has been proved by experience to require 1,200 incandescent (such as Swan's, but for which may be substituted a smaller lights, representing an expenditure of 133 horse power; and number of higher resistance and higher luminosity) requires 200 about one-half that power would have to be set aside for each of volts electromotive force, and 60 Watts for their efficient workthe other public building; here mentioned, constituting an ing, the total current required for 64,000 such lights is 19,200 aggregate of 2,926-horse power ; nor does this general estimate ampères, and the cost of the electric energy lost by this current comprise street lighting, and to light the six and a half miles of in passing through vl·locth of an ohm resistance, is 161. per principal streets of the parish with electric light, would require hour. per mile, thirty-five arc lights of 350-candle power each, or a The resi tance of a copper bar one quarter of a mile in tral of 227 lights. This, taken at the rate of o 8-horse power length, and one square inch in section, is very nearly 1.100th of per light, repre ents a furtber requirement of 182-horse power, an ohm, and the weight is about 2 tons. Assuming, then, the making a total of 3, 108-horse power, for purposes independent price of insulated copper conductor at 90l. per ton, and the rate of of house lighting, being equivalent to one-horse power per interest and depreciation at 73 per cent., the charge per hour inhabited house, and bringing the total requirements up to 10g of the above conductor, when used eight hours per day, is işd. lights = 12-horse power per house.
Hence, following the principle I have stated above, the proper I do not, however, agree with those who expect that gas size of conductor to use for an installation of the magnitude I lighting will be entirely superseded, but have, on the contrary, have supposed, would be one of 48-29 inches section, or a round always maintained that the electric light, while possessing great rod eight inches diameter. and peculiar advantages for lighting our principal rooms, halls, If the mean distance of the lamps from the station be assumed warehouses, &c., owing to its brilliancy, and more particularly to as 350 yards, the weight of copper used in the complete system its non-interference with the healthful condition fof the atmo of conductors would be nearly 168 tons, and its cost 15,120!. sphere, will leave ample room for the development of the former, To this must be added the cost of iron pipes, for carrying the conwhich is susceptible of great improvement, and is likely to hold ductors underground, and of testing boxes, and lab ur in placing its own for the ordinary lighting up of our streets and them. Four pipes of 10 inch diameter each, would have to prodwellings.
ceed in different directions from the centralstation, each containing Assuming, therefore, that the bulk of domestic lighting sixteen separate conductors of one inch diameter, and separately remains to the gas companies, and tbat the electric light is intro. insulated, each of them supplying a sub-district of 1,000 lights. duced into private houses, only, at the rate of, say twelve The total cost of establishing these conductors may be taken at incandescent lights per house, the parish of St. James's would 37,0001., which brings up the total expenditure for central station have to be provided with electric energy sufficient to work (9 and leads to 177,000l. I assume the conductors to be placed + 12) 3,018 = 63, 378 lights 7,042-horse power effective; underground, as I consider it quite inadmissible, both as regards this is equal to about one-fourth the total lighting power re permanency and public safety and convenience, to place them quired, taking into account that the total number of lights that above ground, within the precincts of towns. With this expenhave to be provided for a house are not all used at one and the diture, the parish of St. James's would be supplied with the same time. No allowance is made in this estimate for the electric light to the extent of about 25 per cent, of the total transmission of power, which, in course of time, will form a illuminating power required. To provide a larger percentage of very large application of electric energy; but considering that electric energy would increase the cost of establishment propor. power will be required mostly in the day time, when light tionately; and that of conductors, nearly in the square ratio of is not needed, a material increase in plant will not be necessary the increase of the district, unless the loss of energy by resistfor that purpose.
ance is allowed to augment instead. In order to minimise the length and thickness of the electric It may surprise uninitiated persons to be told that to supply a conductor, it would be important to establish the source of power, single parish with electric energy necessitates copper conductors as nearly as may be, in the centre of the parish, and the position of a collective area equal to a rod of eight inches in diameter ; that suggests itself to my mind is that of Golden-square. If the and how, it may be asked, will it be possible under such conunoccupied area of this square, representing 2,500 square yards, ditions to transmit the energy of waterfalls to distances of twenty vas sexcavated to a depth of twenty-five feet, and then or thirty miles, as has been suggested ? It must indeed be adarched over so as to re-establish the present ground level, a mitted that the transmission of electric energy of such potential suitable covered space wonld be provided for the boilers, (200 volts) as is admissible in private dwellings would involve engines, and dynamo-machines, without causing obstruction or conductors of impracticable dimensions, and in order to transmit public annoyance; the only erection above the surface would electrical energy to such distances, it is necessary to resort in the be the chimney, which, if made monumental in form, first place to an electric current of high tension. By increasing might be placed in the centre of the square, and be combined the tension from 200 to 1,200 volts the conductors may be rewith shafts for ventilating the subterranean chamber, care being duced to one-sixth their area, and if we are content to lose a taken of course to avoid smoke by insuring perfect combustion larger proportion of the energy obtained cheaply from a waterof the fuel used. The cost of such a chamber, of engine power, fall, we may effect a still greater reduction. A current of such and of dynamo-machines, capable of converting that power high potential could not be introduced into houses for lighting into electric energy, l'estimate at 140,000l. To this expense purposes, but it could be passed through the coils of a secondary would have to be added that of providing and laying the con dynamo-machine, to give motion to another primary machine, ductors, together with the switches, current regulators, and producing currents of low potential to be distributed for general arrangements for testing the insulation of the wire.
consumption. Or secondary batteries may be used to effect the The cost and dimensions of the conductors would depend conversion of currents of high into those of low potential, whichupon their length, and the electromotive force to be allowed. ever means may be found the cheaper in first cost, in maintenance, The latter would no doubt be limited, by the authorities, to the and most economical of energy. It may be advisable to have point at which contact of the two conductors with the human several such relays of energy for great distances, the result of frame would not produce injurious effects, or say to 200 volts, which would be a reduction of the size and cost of conductor at except for street lighting, for which purpose a higher tension is the expense of final effect, and the policy of the electrical engiadmissible. In considering the proper size of conductor to be neer will, in such cases, have to be governed by the relative cost used in any given installation, two principal factors have to be of the conductor, and of the power at its original source. If