Page images
PDF
EPUB

compulsory colour examination (in many cases a most inefficient | MESSRS. J. AND A. CHURCHILL are publishing a second one) to be passed before a sailor can become an officer, there is | edition, revised and enlarged, of “Commercial Organic no check to a colour-blind man being a sailor, or to his remain Analysis," by Alfred H. Allen. The second part of the third ing one to his life's end.

volume has just appeared. The third part of the same volume

will be issued as soon as possible, and will complete the work. The Rev. T. A. Marshall describes in the November number

In the second part he has sought to describe fully and accurately of the Entomologist's Monthly Magazine a new genus and

such of the organic bases as have any practical interest, and to species of Belytidæ from New Zealand. The paper is accom

give trustworthy information as to their sources. panied by representations of two insects in fine condition. Mr. Marshall abstains from giving tedious details, as the figures

The new number of Natural Science includes articles on the will, he believes, convey a better idea of these creatures than

evolution of consciousness, by C. Lloyd Morgan; primæval many words, and he thinks they will now be unmistakable, man : a palæolithic foor near Dunstable, by W. G. Smith ; at least until other species of the same genus shall be discovered. the evolution of sharks' teeth, by A. S. Woodward ; the walk of He has not taken any characters from the under-side, the arthropods, by G. H. Carpenter; the falling of leaves, by A. specimens being carded; hence the oral organs could not be B. Rendle ; and Norwich Castle as a museum, by H. Wooddescribed, but they may be pretty safely assuined to resemble

ward. those of Belyta, Anectata, &c., and their details would have A REVISED edition of "London Birds and London Insects," been of little value.

by Mr. T. Digby Pigott, has been issued by Mr. H. Porter.

Along with the essays on these subjects have been printed A CORRESPONDENT of the New York journal Electricity,

several other bright and attractive sketches. writing from Paris, describes some electrical peculiarities which he has seen in a cat. This cat, called Michon, is a half wild

An elaborate index to the genera and species described in the animal, and dislikes handling. It belongs to the household of

“ Palæontologia Indica," up to the year 1891, by W. Theobald, Dame Gais, whose residence on the Carnier Mount, near

has just been issued. It is included among the Memoirs of the Monte Carlo, looks directly down on the noted gambling casino

Geological Survey of India. Mr. Theobald has also preand its botanical reservation. On some of the cold and very

pared "Contents and Index of the Memoirs of the Geological dry nights common to Monte Carlo in the winter, Michon,

Survey of India, 1859 to 1883."

surve while in the dark, is quite a spectacle. Every movement of its A Second edition of Dr. F. H. Hatch's “Text-book of body sends off hundreds of minute bluish sparks, something like Petrology” has been issued by Messrs. Swan Sonnenschein those thrown off by ill-adjusted brushes, though not so pro- and Co. The author explains that he has taken advantage of nounced in colour. They make a noise on a small scale, like this opportunity to revise the book thoroughly, while largely the crackling of burning furze. Stroking the cat increases the increasing its scope. sparking, and ruffling its fur the reverse way produces a minia.

The Society for Promoting Christian Knowledge has pubture pyrotechnic display quite remarkable. The cat itself does

lished a second edition of Klein's “Star Atlas." Mr. E. not seem to mind the sparking, but, like all cats, dislikes to have its fur rubbed in a wrong direction.

| McClure, the translator of Dr. Klein's explanatory text, has The writer has never seen

sought to bring up to date the German writer's descriptions of the electric element so abundant in a cat, and many who have seen the coruscations that have

the more interesting fixed stars, star clusters, and nebulæ.

given notoriety to Michon, confirm him in the opinion that the cat is an

MESSRS. ROBERT GRANT AND Son, Edinburgh, and electrical curiosity.

Messrs. Williams and Norgate, London, have issued Parts II.

and III. of Vol. XXXVI. of the Transactions of the Royal A USEFUL account of “Biological Teaching in the Colleges Society of Edinburgh. The following are the subjects of some of the United States," by Prof. John A. Campbell, of the of the papers :-the foundations of the kinetic theury of gases University of Georgia, has been issued by the United States (IV.), by Prof. Tait; the solid and liquid particles in clouds, Bureau of Education. The writer's object is to present the actual by J. Aitken; the development of the carapace of the chelonia, extent and scope of the biological courses offered by the colleges by J. B. Haycraft; the composition of oceanic and littoral of the United States, together with the methods of teaching manganese nodules, by J. Y. Buchanan ; the winds of Ben employed. He also aims at presenting as fully as possible an Nevis, by R. T. Omond and A. Rankin ; and the Clyde sea account of the equipment and facilities for teaching which the area, by H. R. Mill. various colleges possess. The statements he makes are there

The University College of Wales, Aberystwith, has issued fore based largely upon the printed accounts found in the college lite

its calendar for its twenty-first session, 1892-3. catalogues, supplemented in many cases by letters containing additional information. These have usually been re-written,

The City and Guilds of London Institute has issued its probut where they are in suitable form they are quoted directly.

| gramme of technological examinations for the session 1892-93. Prof. Campbell notes that many of the colleges announce more Messrs. George Philip AND Son announce that a work on in their catalogues than they can possibly do thoroughly with the “ British New Guinea," by Mr. J. P. Thomson, Hon. Sec. to teaching force employed. This is often perfectly apparent, but the Brisbane Branch of the Royal Geographical Society of Ausin more than one letter received the statement has been inade tralasia, is almost ready for publication. An appendix will conthat certain courses have no existence save on paper. Prof. tain contributions to the geology, fauna, fora, &c., by Sir Campbell, however, thinks that it is worth while to record the William Macgregor, K.C.M.G., Baron Ferdinand von Mueller, views of the professors in charge in regard to the nature and Professor Liversidge, F.R.S., and others. The proof-sheets aims of such work, and the ideals towards which they are have been revised by Dr. H. Robert Mill and Dr. Bowdler striving.

Sharpe. THE “ Treatise on Hygiene and Public Health,” edited by ANOTHER and apparently much more convenient mode of Dr. T. Stevenson and Mr. Shirley Murphy, and reviewed in preparing glycol aldehyde, CH,OH.CHO, the first member of NATURE last week, is published by Messrs. J. and A. the series of aldehyde-alcohols, is described in the current Churchill.

number of the Berichte, by Drs. Marck wald and Ellinger, of

[ocr errors]
[ocr errors]
[ocr errors]

31 51 ...

[ocr errors]

1892.

[ocr errors]

Berlin. It may be remembered that in our note of a fortnight

OUR ASTRONOMICAL COLUMN. ago (vol. 46, p. 596), it was announced that Prof. Emil Fischer and Dr. Landsteiner had succeeded for the first time in pre

ComeT BROOKS (AUGUST 28).—The following ephemeris,

which we take from Astronomische Nachrichten, No. 3125, paring this interesting substance in a state of tolerable purity by

gives the apparent Right Ascensions and Declinations of Comet a reaction analogous to that of barium hydrate upon acroleîn Brooks, which is brightening very rapidly :dibromide, the reaction which yielded the first synthetical glu

12h. Berlin M.T. cose. They first prepared the mono-bromine, derivative of common aldehyde, CII,Br.CHO, and subsequently reacted upon this new

R.A. app. Decl. app. Log. r. Log. A. Br.

1892. substance, a liquid possessing an intolerably sharp odour, with | Nov. 3 ... 9 23 51

+9 5518 baryta water. After removal of the baryta by sulphuric acid,

27 50 9 98 ... 0'1265 ... 0°0225 ... 1160 and the hydrobromic and sulphuric acids by means of carbonate of lead, a liquid was obtained which possessed the properties of

... 7 34:6

40 I ... 6 45'4 a dilute solution of glycol aldehyde. Some time ago Pinner 8 ... 44 10 ... 5 55'2 ... 0'1125 ... 0'0034 .. 13:51 obtained a derivative of this aldehyde which bore the same rela

48 21 ... 54'0 tion to glycol aldehyde, that the compound known as acetal, 10 ... 52 34 ... 4 1.8 OC,H,

Lying in the extreme northern corner of the constellation of CH.CH , bears to common aldehyde. This substance, Sextans, and nearly midway between p Leonis and e Hydra, oc,H,

it will not be an easy object sor observation owing to its very , OCH

late rising. glycol acetal, CH,OH.CH , Pinner attempted to de"Toc,H;

COMET BARNARD (OCTOBER 12).-Prof. R. Schorr, of

Hamburg, communicates to Astronomische Nachrichten, No. compose, by the action of mineral acids, into ethyl alcohol 3125, the elements and ephemeris of Comet Barnard, deduced and glycol aldehyde. The attempt, however, did not succeed, from observations made on October 16, 18, and 20, at Vienna, inasmuch as the decomposition went further, any glycol alde

Hamburg, and Pulkowa respectively. As this ephemeris differs hyde that may have been formed during the first stage of the

rather considerably from the one we gave last week, the follow

ing places may prove of service to observers :reaction being subsequently broken up. Drs. Marckwald and Ellinger now find that the reaction succeeds admirably, pro

12h. Berlin M.T. vided the acid employed is extremely dilute, and as glycol

R.A.

Decl. Log . Log A. Br. acetal is a substance very easily prepared, they show that the | Nov. 3 ... 20 24 38 ... +5

Nov. 3. ...

37 reaction affords a very convenient and advantageous method

... 4 44 0 of preparing large quantities of glycol aldehyde. The glycol

4 246 ... 0'2298 ... 0'1539 ... 1'00 acetal is added to an equal volume of water acidified with only

4 54 a few drops of sulphuric acid. The liquid is then heated to

... 3 464 boiling. After a short time the two liquids mix, and the reaction

38 21 ... 3 27.8

9 ... 41 9... 3 94 .. 0'2278 ... Oʻ1590 ... Oʻ99 is completed when upon the addition of water to a few drops 10 ... 43 58 ... 2 512 of it no separation of oil occurs. Upon distilling the liquid

This comet will still be found to form approximately an equilateral product, alcohol first passes over, then there distils a mixture

| triangle with a Aquilæ and B.Delphini on November 5. of water and glycol aldehyde until decomposition of the residue

TABULAR HISTORY OF ASTRONOMY TO THE YEAR commences. Glycol aldehyde, as thus obtained in a tolerably | 1500 A.D.-Dr. Felix Müller, of Berlin, has just completed a concentrated form, appears to be much more volatile in steam small volume entitled “Zeittafeln zur Geschichte der Mathethan was observed by Prof. Fischer and Dr. Landsteiner, in

mathik, Phisik und Astronomie bis zum Jahre 1500," which case of their more dilute solutions. From a few cubic centi

will be welcomed by all interested in the very early history of

the exact sciences. The book is arranged chronologically and metres of the distillate Drs. Marckwald and Ellinger obtained

gives a short account of the chief workers in these branches of a very considerable quantity of Prof. Fischer's phenylhydrazine science up to the year 1500. At the end of each reference a compound, and confirm in every detail the other properties of list of the literature likely to be needed is added. The work is glycol aldehyde described in our previous note above referred published by Messrs. B. G. Teubner, Leipzig. to. The chemistry of this first member of the series which in A LARGE TELESCOPE,—The Americans seem to have made cludes the sugars is now, therefore, fairly complete, and the up their minds to be the possessors of the largest telescopes in difficulties in the way of its preparation surmounted.

existence, for in spite of their owning the great Lick Refractor

| (36-inch) we hear now that the University of Chicago are about The additions to the Zoological Society's Gardens during the to have the largest and most powerful telescope in the world." past week include a Rhesus Monkey (Macacus rhesus 8 ) from This instrument will be the gift of Mr. Charles Jerkes, and will India, presented by Mr. Pascoe Grenfell, F.Z.S. ; a cost half a million dollars. The object-glass will have a diameter Philantomba Antelope (Cephalophus maxwelli) from West

of 45 inches and will be made by Messrs. Alvan Clark, of Africa; three Gambian Pouched Rats (Cricetomys gambianus)

Cambridge, Mass. from West Africa ; a Ground Rat (Aulacodus swindernianus)

THE ATMOSPHERES OF PLANETS. — Of all the planets that

revolve round our sun, Jupiter affords the most suitable of them from West Africa ; and a White-faced Tree Duck (Dendrocygna

for the study of atmospheric circulation. That his circulation viduata) from West Africa, presented by Mr. C. B. Mitford ; will not be exactly like ours will be at once evident, for not only a Martial Hawk-Eagle (Spizaetus bellicosus) from South Africa, does the sun pour his rays on his vast surface, but he possesses presented by Mr. T. White; two Weaver Birds (Hyphantornis | himself heat, as is suggested by the rapid changes which these sp, inc.) from South Africa, presented by Mr. A. W. Arrow

cloud massez undergo. A recent hypothesis, explaining the

various movements in this planet's atmosphere, has been put smith ; two Silver Pheasants (Euplocamus nycthemerus 8 8)

forward by Mr. Marsden Manson, in the fifth number (vol. ix.) from China, presented by Mr. E. Mitchener ; a Common of the “ Transactions of the Technical Society of the Pacifc Chameleon (Chama!con vulgaris) from North Africa, presented Coast,” San Francisco. The chief element which produces by Miss Kate Higgins; a Thick-tailed Opossum (Didelphys

these movements is the action of the sun, and it is on this reasoncrassicaudata) from South America; a Garden's Night-Heron

ing that he attempts to unravel the laws underlying the circu

lation in Jupiter's atmosphere. In this pamphlet he first brings (Nycticorar gardeni); and two Saracura Rails (Aramides

together some of the facts relating to our own wind system, saracura) from South America, purchased ; and a Squirrel which are generally conceded, together with the important Monkey (Chrysothrix sciurea) from Guiana, deposited.

results that were gathered from the path taken by the Krakatoa

[ocr errors]

dust.cloud. The spots observed on Jupiter's surface are next countered from the terrible extremes of heat and cold. The dealt with, a table of their rotation periods and latitudes last few thousand feet proved very exhausting ; one of the being included. From the latter he deduces that the mean Gboorkas had to be left behind, suffering from mountain-sickperiods of rotation of matter in the following latitudes are : ness. Every step had to be cut in hard ice. Finally the summit

h. m. s.

was reached at an elevation of 23,000 feet ; but the Golden 12° N. from 17 N. Temp. spots 9 55 36-49

Throne stood revealed much higher, and separated by a deep 4° N. , 5 N. Equat. , 9 50 40'06

depression. From the summit of Pioneer Peak, probably the 8° S. ; 21 S. Equat. 9 50 22 4

highest yet reached by man, a series of photographic views was 30° S. 3 spots

9 55 17'1

obtained and prismatic compass bearings taken to the surroundIn treating of the spots themselves, he suggests that those which

ing features. As long as ibe party were at rest they felt no

discomforı, but the sphygmograph showed that the heart's are of a white appearance are gyrating uprushes of warm air

action was very laboured. A stay of an hour and a quarter from the lower regions, while the dark ones are simply descend

was made on the suminit, the view from which baffled descriping columns of cool air, “the two forming parts of the system of vertical circulation.” The red spot, he suggests, is caused by a

tion. The descent was salely made, but satigue and bad weather local escape of internal heat, the repellent force it appears to

| stopped further exploration. possess being due to the “ spreading of the heated currents as they rise." He explains the retardation and acceleration of its period of revolution by the increasing force of the west winds, brought THE INSTITUTION OF MECHANICAL about by the exposure of the southern hemisphere during Jupiter's

ENGINEERS. half-year (5'93 of our years); in this way the spot is sometimes situated over and sometimes to one side of the source of heat

ON the evenings of Wednesday and Thursday of last week, the underneath. The author also deals with other spots in a similar

V 26th and 27th ult., an ordinary general meeting of the Instimanner.

tution of Mechanical Engineers was held in the theatre of the Institution of Civil Engineers, by permission of the council of the latter Society. The President, Dr. William Anderson, occu

pied the chair during the proceedings. GEOGRAPHICAL NOTES.

There were iwo papers on the agenda. The first was the MR, SVEN Hedin's account of his ascent of Mount Demavend

report of the Institution's committee appointed to enquire into is published in the last number of the Verhandlun en of the the value of the steam jacket. Mr. Henry Davey is the chairBerlin Geographical Society. Demavend is a volcanic peak

man of his committee, and he had prepared the report ; rising abruptly from the sedimentary rocks of the parallel Elburz

which is a bare record of facts without comment, and in this chains. Starting from the village of Ranah on the south respect is, we think, defective. Numberless experiments have eastern slope with two guides on July 10, 1890, Hedin reached

been made in time past as to the value of the steam jacket, and the summit on the afternoon of the next day. On the summit a

those now added by the labours of the committee do not largely large elliptical crater was found ; the edges of which were strewn

differ from many that have gone before. We take it that the with blocks of porphyritic lava and sulphur. After discussing

general opinion of competent engineers is that an advantage in the aneroid and boiling point observations. Mr. Hedin arrived efficiency is to be obtained by jacketing engine cylinders in an at 5465 metres (17.930 feet) as the height of the summit. This | efficient manner, and cases in which the jacket has not been is lower than any of twelve earlier estimates which are cited, the

proved efficient are those in which it has not been properly aphighest of them being 6559 metres.

plied. What was wanted, therefore, was guidance as to the

proper method of application, and it is significant that the The Italian possession of Eritrea on the coast of the Red Sea

most help in this direction came, during the discussion, from gives some promise of becoming uselul agriculturally. Several

those who were not members of the committee. Timidity in exsmall settlements of Italians on the plateau have succeeded in

pressing opinion will be excusably construed as indicating somegrowing large crops of wheat and barley, and only the unsettled

ihing of incompetence, and if the members are not capable of state of the surrounding natives threatens the prosperity of the farmers. The districts of Oculé-Cusai and Guro are already

expressing opinion they are not suitable persons to form a research

committee of an important institution. We frame our remarks fully cultivated, and Saraé, as yet almost unoccupied, has fertile

hypothetically, because, with such names as Unwin, Bryan Don. land and plenty of room for colonists. The Italians are able to

kin, and Mair-Rumley on the title-page, there can be no doubt work in climatic conditions which would rapidly exhaust the

that the power to afford guidance was present, and sor this natives of northern Europe.

reason the decision to give only bare fact is the more to be reTHE general summary of Mr. Conway's expedition in the gretted. The general conclusion to be drawn from the Karakoram range telegraphed from India (p. 525) has now been experiments, as quoted, is that “the expenditure of a quantity supplemented by a full narrative, written to the secretaries of l of steam in an efficient jacket produces a saving of a the Royal Geographical Society from a camp on the Baltoro greater quantity in the cylinder.” It does not follow Glacier on August 29, with a postscript added at Skardo, on the from this ihat the jacket is always desirable, as the saving may way to Leh, on September 12. The difficulties of the pre- / be so small as not to justify the additional complication and liminary journey were very great, not the least being the fording | increased outlay at first cost. That, however, is a matter of several swollen glacier streams by a party numbering four upon which steam users must themselves decide upon a comEuropeans, four sepoys, seventy coolies, an indefinite number of mercial basis ; and is, of course, outside the province of the followers, and flocks of goats and sheep. The moraines on the committee, but what would have been valued would have been Baltoro glacier were of almost incredible extent ; for two-thirds of some critical remarks giving guidance as to what goes to conits entire length the ice is entirely concealed by słones, except where | stitute the “ efficient jacket,” what fresh engineering practice is crevasses or lakes occur, and the irregularity of the surface made opened up by the use of the efficient-jacket, and under what contravelling extremely slow. Mr. Conway limits the name ditions it may be most effectually applied. of Godwin.Austen to the highest peak of “K?,” giving The first series of experiments quoted were carried out by to the whole mountain the somewhat cumbrous title Mr. J. G. Mair-Rumley, of the firm or James Simpson and Co., of the Watch Tower of India. One branch of the of Pimlico, upon a compound jet-condensing beam pumpingBaltoro Glacier results from the union of seven glaciers | engine. The diameters of the cylinders are 29 inches and from this mass ; the larger branch descends from the 47.5 inches, with strokes of 651 and 96 inches respectively. snow-swathed, throne-shaped mountain, hitherto unmapped, Only the body of cach cylinder is jacketed, the steam being for which the auriserous quartz found in its rocks suggested supplied direct from the boiler at a pressure of 49lbs. per square the name of The Golden Throne. This was fixed upon as the inch above atmosphere. Experiments were made both with goal to be attained. The first attempt landed the Europeans and without steam in the jackets. The total seed water per and Ghoorkas, who made excellent climbers, on Crystal Peak, indicated horse power per hour when the jackets were not in 20,000 feet in elevation, a peak as hard to climb as the Matter use was 18'20 lbs., with the jackets in use the corresponding hors, and isolated from the surrounding higher summits. No figures were 16 64 lbs., Thus showing a percentage of less steam inconvenience was felt from the rarity of the air, and the party used due to the jackets of 8:6. The quantity of jacket water remained on the summit for an hour and a quarter. In the condensed was i'20 lbs. per I.H.P. per hour. The boiler pressure grand attempt on the Golden Throne serious difficulty was en: here was not high, 4997 lbs. without and 49 lbs, with jackets. The number of revolutions were also low, 148 without jackets | was therefore 73 per cent. The jacket water used per and 15.78 with jackets. This was evidently an engine which | I.H.P. per hour was 2-40 lbs. We regret we are not able to should pay for jacketing. We next come to an experiment of | give all the interesting details which Prof. Unwin includes in a different nature, carried out by Mr. Davey and Mr. W. B. his instructive report, but for these we must refer our readers to Bryan. The engine is triple expansion surface-condensing the original paper. engine of the inverted direct-acting marine type, and is placed Probably Prof. Unwin's 7'3 per cent. saving in steam used is in The Waltham Abbey pumping station of the East London a far better measure of the value of the jacket than the inflated Water Works. The cylinders were 18", 30'5", and 51" in I promise of 19 per cent. in Major English's trial. It should be diameter, by 36 inches stroke. There is a Meyer expansion remembered that the jacket is more effective in small than in valve to the high pressure cylinder, by means of which the speed | large engines, the area of cylinder will be in a higher ratio to the of the engine was regulated during the experiment. The bodies contained steam in the former than in the latter case. The number and both ends of all three cylinders are steam-jacketed. The of expansions in the South Kensington engine working without jacket steam of the high pressure cylinder is at full jackets was 7'23, and with jackets 9'29. The corresponding boiler pressure, but the other two cylinders have the figures in the case of the Woolwich engine were 9.4 and 12-6. pressure reduced to a little above that of their steam-chests by The boiler pressure with the Woolwich engine was, however, means of reducing valves. Each cylinder is therefore jacketed 16 to 17 lbs. higher than in the other case. The revolutions with steam a little above its own initial pressure. Without the were 57'06 and 63 62 respectively in the two trials at Woolwich, jackets in use the amount of seed water per I. H.P. per hour whilst at South Kensington they were 93 66 and 96'11. It was 17.22 lbs, and with the jackets in use 15.45 lbs, showing a would have been instructive is the committee had had the percentage of less steam used owing to the jacket of 10'3. The courage to attempt some balance of these figures, and then have total jacket water was 1'72 Ibs. per I.H.P. per hour. The coal endeavoured to account for the large difference which we believe consumption is given in these experiments, being 2'09 lbs. per would have remained still to be accounted for. I.H.P. per hour without the jackets, and 1479 lbs. with. The The next experiments quoted comprise a series made by Mr. amount of coal burnt is not, of course, necessarily a measure of Bryan Donkin, judr., at the works of his firm at Bermondsey. economy of the engine, but possibly the steam-generating plant Mr. Donkin's labours in this field are well known, and engin- which included an economizer--was practically constant in its! eering science is largely indebted to him for the contributions he duty during both trials, and if so the commercial gain by the has made to its lore. One most valuable feature in connection use of the jacket is quite an appreciable quantity. The boiler with these investigations is the means he has used to ascertain pressure here was 130 lbs. above atmosphere, the number of the temperature of the walls of the cylinder at various distances expansions without the jacket 22, and with the jacket 30. The from the surface. In this lies the essence of the problem. If revolutions were 23 per minute, so that the jacket had again a the Jackets Committee would give us minute and trustworthy favourable chance.

information on this point we could evolve the rest from existing The next series of experiments were carried out by Colonel data. If we do not quote Donkin's figures in full it is English, Mr. Davey, and Mr. Bryan Donkin, and in these we partly because his experiments are not yet complete and partly reach a much higher piston speed, so that the results stand on a because they have been dealt with more fully in “another somewhat different footing in this respect to those besore quoted. ! place," namely, the Proceedings of a Society other than tha We have no positive knowledge of this engine beyond that given with which we are now dealing. We may state, however, in the report, but it would be desirable to know something that in one case when the steam in the jacket space was 298* more of its working before accepting the very high percentage of Fahr. the cylinder walls averaged 290° Fahr., whilst at o'o6 in. gain in steam used-19'0 per cent.-as that due to a steam from the piston the temperature of the cylinder wall was 284* jacket used on a good engine. The feed used per I.H.P. per Fahr. These temperatures were ascertained by thermometers hour was 24.68 lbs. without the jacket, and with the jacket in placed in holes drilled in the cylinder. Other instances are use the quantity was 20 lbs. The following are the particulars given, but the matter is far too interesting to deal with in a of this trial :-Horizontal surface condensing compound engine, cursory manner, such as a report of this nature alone warrants. with intermediate receiver cylinders, 18 and 32 ins. by 48 ins. The difficulty that suggests itself is the fact that a thermometer stroke. The ends of the cylinders are not jacketed, and the itself has a very appreciable thickness, and the record will be receiver jacket was not in use during the experiment. The but a mean of the temperature due to that thickness. It is posboiler pressure was 50 lbs., the revolutions 57.06 without jackets, sible that Mr. Dopkin gets over this difficulty in some way. and 63:62 with, the seed water supply as stated, and the jacket Perhaps the thermo-couple as used by Le Chatelier migbt water condensed per I. H.P. per hour l'13 lbs. The coal used afford a solution, although this apparatus is not so useful without jackets was 3:26 lbs. per J.H.P. per hour, and with for recording small differences at low temperatures, being jackets 2:66 lbs.

rather adapted for such work as hot blast stoves and other The last set of experiments we shall quote were made by Prof. metallurgical purposes. Mr. Bryan Donkin's experiments are Unwin, upon the experimental engine 1' at the City and Guilds the most suggestive in the report, as might be anticipated. of London Central Institution, South Kensington. It is a two Trials were made with steam at various rates of expansion to cylinder horizontal-surface condensing engine, and can be worked determine the effects of the steam-jacket on the speed of engine either simple or compound. The cylinders are 8.73 inch and and temperature of the cylinder walls, and on superheating. 15-76 in diameter, by 22" stroke. The high pressure cylinder The engine used was a small one (6" x 8"), but it was specially is fitted with Hartnell expansion gear, and the low pressure with constructed and arranged for the work. We again repeat Mr. Meyer expansion gear. Only the bodies and the back ends of Donkin's investigations are well worthy of the study of all the cylinders are covered. We will first give results of trials interested in these matters. working the engine with the low pressure cylinder only. The The report concludes with a valuable appendix in the shape of pressure was 60 lbs. above atmosphere, the jacket pressure being suggestions for the use of those desirous of experimenting in taken direct from the boiler. " The revolutions without the this field. jacket were 112'40, and with the jacket 10173. The feed The discussion on this paper was of a protracted nature, bat water per J.H.P. per hour without the jacket was 32'14 | was not of a kind altogether worthy of the leading mechanical Ibs., and with the jacket 26.69 lbs. This gives a saving institution of the country. Mr. Morrison, of Hartlepool, made of 17 per cent. working simple. It will be seen presently that the most weighty contribution amongst the speakers. He pointed when the engine was working compound, the saving was 7'3 per out the difficulty of maintaining a good circulation of steam in cent. The jacket-water per I.H.P. per hour was 1.88 lbs. the jacket-one of the most important points to which the We will now take the records of the compound trial. The boiler | designer of jacketed engines should turn his attention-and pressure was 66.73 lbs. without the cylinders, and 67:80 lbs. illustrated a simple method by which he had secured this end with the jackets. The revolutions were 93:66 without the His arrangement consisted of a series of diaphragms, by means jacket, and 96:11 with. The feed water used per I.H.P. of which the steam was made to take a devious course throogt per hour was 21'06 lbs. without the jackets in use, and 19:52 the jacket. Mr. Schonheyder pointed out a mistake the con lbs, with. The saving, as stated, made by the use of the jacket mittee had made in placing an air-cock on the top of the jacket,

when it was required to draw off air from the steam. Or course, 1 This engine is stated in the report to have been fully illustrated and this is one of those little slips which the wisest are apt to make, described in Engineering of November 16, 1888. The triple expansion for it would be absurd to suppose such authorities as those enengine at Waltham Abbey is also said to have been illustrated and described in the issue of August 8, 1892, of the same publication.

See Proceedings Inst. Civil Engineers.

er

gaged did not know that air is heavier than steam. One might Matthey, so largely helped forward the principal work of the as well say one's grocer did not know sand from sugar.

committee ; the metallurgical studies of Stas are indeed recog. The Jackets Committee has not yet concluded its labours, and nized as veritable models of classical research in this particular another report will be forthcoming in due course. Mr. Aspinall field. has offered a locomotive for trial, and we heard that Mr. Yarrow The new instruments added to the Bureau at Sèvres during will put a torpedo boat at the disposal of the committee, and the last year include a normal barometer (le Baromètre Fuess) has even promised to cast special cylinders for experimental pur and manometer, originally verified for reference as an interposes. The locomotive will afford an interesting field of research, national standard in accordance with the decisions of the running as it does so largely linked up. The torpedo boat

Meteorological Conferences, particularly that at Munich last experiments will be no less interesting, especially in view of the year. The committee have also obtained a new apparatus for great number of revolutions the engines of these crast make in a determining the normal thermometric “boiling point," or the given time.

temperature of 100° Centigrade, as it has been found that the On the second day of the meeting the paper by Mr. Walker form of apparatus used by Regnault was unreliable for this purof Bristol on the screw propeller. This paper gives the details! pose. In the reading of the standard manometer it would apof some experiments made by the author on a form of screw pear that higher accuracy has been obtained by raising the propeller invented by the late Mr. B. Dickinson. It would be surface of the mercury up to a fixed point, the image of the in vain for us to attempt to condense this paper within the point in the mercury being observed at the same time by means limits at our disposal. With regard to the merits of the of a microscope. The Wild-Pernet barometer has been reDickinson propeller we have nothing to say. It consists | mounted, and the Bureau are now prepared to undertake the essentially of two narrow blades in place of one, and reminds | verification of any standard barometer. us strongly of a Mangin propeller with one blade set somewhat | The readings of all mercurial thermometers are given at the back on the shaft. Mr. Walker contends that his researches Bureau in terms of the hydrogen thermometer ; and a 30

litre holder prove the advantages of long narrow blades, but he did not litre holder for methyl chloride, or liquid carbonic acid, has been appear to have converted the high authorities present, including made by Brigonnet and Navile. The low temperature experi. Mr. Froude, Mr. Thorneycroft, and Mr. Barnaby—the three

ments have been continued by M. Chappuis down to ~75° Cent.; best-known names in connection with the subject to his views. and toluol and alcohol thermometers have been compared with It is difficult to see wherein the value of the paper exists. Prof. | the hydrogen thermometer. It has been found tbat “toluol” is Kennedy in the discussion stated that the generally received more sensitive and reliable for low temperatures than alcohol. opinion as to the increase of the friction of the load was

We note that the meteorological work of the committee has erroneous, and that the power absorbed in this way does not largely developed itself; and that, as in geodetic research, increase in the manner stated, a fact which he illustrated by

the Bureau at Sèvres is now recognized as a central and intermeans of a diagram. Mr. Thorneycroft pointed out that “life

national station of reference. Standard thermometers have was not long enough " for the larger trials proposed by the author,

been verified, for instance during 1892, for the Governments of but that he might decide one point if he would confine himself

Russia, France, and Roumania ; for the Universities of Rome, to models. Mr. Barnaby stated that a broad-bladed propeller

St. Petersburg, and Odessa ; for Owens College, Manchester; should not be a uniform pitch. Mr. Froude's speech was a lucid

and for several recognized meteorological observatories. Great criticism of the author's paper, the speaker pointing out in a

Britain has also been supplied by the committee with standard kindly but convincing manner that the conclusions arrived at

thermometers similar to those supplied to other contracting by the author might be subject to revision. Mr. Dunell, States. whose previous experiments the author had quoted, added to

Besides the standard metre and kilogramme already delivered the information given by putting forward some other experiments

to this country, the Bureau is undertaking the construction of a he had made upon screw propellers fitted to a torpedo boat, in

further standard metre for the Board of Trade, at a cost of this case the results being opposed to those claimed by the

12,588 francs. The new standard appears to have been nearly author, inasmuch as the shorter and broader blade had proved

two years in construction, but its verification is now promised the more advantageous. Mr. Shield, of Liverpool, described a

this year. form of propeller which has been in use on the Mersey, and

There are twenty.one different governments who have joined appears to offer some advantages. The blades are attached to

the Convention and who contribute annually towards the the boss in two parts, and are joined in a loop at the top.

expenses of the Bureau (the annual budget of which is 75,000 According to Mr. Shield's statement, the arrangement gives

francs), sums varying from 134 francs (Denmark) to 9482 francs great advantages in towing, and also increased steadiness in

(Germany) the annual contribution of Great Britain and Ireland running. The latter we can accept as a fact, but the great

for 1892 being stated at 4699 francs, or nearly £188 ; and that increase in towing capacity seems almost too good to be

of the United States at 8471 francs. accepted literally. Twenty five per cent. additional efficiency

At the instance of Dr. B. A. Gould the committee are now also is a very large gain without further expenditure than an

undertaking an inquiry affecting measurement by light waves. exchange of screws; but this is what the propeller in question

By the use of the - Refractometer" Dr. Michelson found is said to realize.

(Philosophical Magazine, April, 1891, and September, 1892) The meeting concluded with the usual votes of thanks.

that accuracy of measurement by light-waves may be increased to a high degree of accuracy. By the best spectroscopic instruments now in use it has been stated to be difficult to " resolve"

lines as close together as the components of the yellow sodium INTERNATIONAL COMMITTEE OF WEIGHTS lines, but that if the width of the lines themselves be less than AND MEASURES.

their distances apart, then there is no limit to their accuracy of THE InternationalCommittee of Weights and Measures, which

measurement by the “Resractometer.” We shall look forward

with interest to ihe publication of Dr. Michelson's further results, was established in consequence of the Metric Convention

in the next volume of the “ Travaux et Mémoires” of this of 1873, has recently issued its fifteenth annual report to the

committee. Governments represented at that Convention. The committee bave also lately published the minutes of their proceedings

The new instrument designed by M. Gustave Tresca, of the (Procès-Verbaux des Séances. Paris, 1892.

Conservatoire des Arts et Metiers at Paris, for the adjustment

vol. Svo) at the annual meeting held at Paris in September, 1891. It appears

and polishing of the terminal surfaces of end-measures of length to be hardly possible that the proceedings of the committee at

appears also to be better than anything yet adopted in England. their meeting which was held last month may be issued before dards and instruments for the High Contracting Governments

The committee not only underrakes the verification of stannext year, but from the above publications, as well as from a recent volume of their “ Travaux et Mémoires,” we gather that

(who have the right to demand such verification ), but they also they continue to carry on their investigations with all de-patch.

verify for any scientific authorities or persons. To those of our In their last report the committee deplore the death of their

readers, therefore, who may desire to have standards or instrucolleague, Jean Servais Stas, whose analyses of the platinum

ments verified by the committee, the following information may

be useful: alloys have, together with those of St. Claire Deville and George Applications for the verification of instruments should first be

1 Rapport du Comite Internacional. Gauthier. Villars. Paris. Vol. made to M. le Directeur du Bureau International (Dr. Renésp PP., 1892.

| Benoit), au Pavillon de Breteuil, Sèvres, près de Paris.

« PreviousContinue »