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districts in this part of America, a discovery of the the edges; and the portions missing probably amount to occurrence of this substance in large masses has been more than half the original crystal. The stone, which recently made in the Cretaceous deposits of Kreischerville, has been named the Cullinan diamond, weighs 9600-5 Staten Island, N.Y. The amber, which is being ex grains troy, or 1.37 lb. avoirdupois; this is more than tensively worked for commercial purposes, occurs in a bed three times the weight of the largest diamond previously containing layers and masses of vegetable débris, together known. with lignite and pyrite. The bed appears to be lens

Some account of the Mount Morgan Gold Mine, Queensshaped. Some at least of the amber is presumed to be

land, is given by Mr. E. J. Dunn (Proc. Royal Soc. the product of sequoias, but it is possible that a species

l'ictoria, vol. xvii., part ii.). The hill, which rises to a of Pinus, and perhaps a representative of the Austro

height of 580 feet, is formed mainly of igneous rocks, Malayan genus Dammara, may have contributed to its

within which are enclosed masses of decomposed rock, production. The remaining articles include one by Prof.

made up of siliceous and ferruginous material, and overHallow on the structure of the vascular cylinder in hybrid

lying these is a plug of Desert Sandstone, nearly 100 feet catalpa trees; a second, by Messrs. Cushman and Hender

thick in places. The sandstone occupies a hollow in loose son, on fresh-water rhizopods from New Hampshire; and

sandy beds overlying a ferruginous layer, and these beds a third, by Dr. F. W. Carpenter, on the behaviour of a

yielded the rich secondary ore for which Mount Morgan fruit fr under certain stimulants.

has been celebrated. No naturally formed gold is known DESCRIPTION of the large diamond found recently in that more nearly reached chemical purity. At a much The Premier Mine, Transvaal, is given in the Geological | lower depth, in what is known as the sulphide zone, the Vagazine (April) by Dr. F. H. Hatch and Dr. G. S. gold is much alloyed with silver. The silver was got rid Corstorphine, with reproductions of four photographs of in the transference of the leached ore to the enriched which represent the diamond in its actual size from four zone. The state of subdivision of the gold in this zone

was so extreme that rich samples, in some cases those carrying 50 oz. per ton, showed no traces of gold that could be detected by the naked eye. The author attributes the formation of the secondary ore to the mechanical and chemical action of sea-water on the sulphide ore, there being evidence of considerable local erosion before the horizontal beds of Desert Sandstone were laid down.

The Canadian Department of Marine and Fisheries has published the meteorological results obtained at the magnetical observatory at Toronto for the year 1904, with remarks, in a handy and useful form. The monthly means are in most cases compared with an average of sixty-four years, and are consequently of considerable value. The mean temperature of the year 1904 was 42o.2, being 2°:2 below the average. The maximum daily mean was 780-9, on July 18, and the coldest day –89.5, on January 14. The rainfall measured 30-04 inches (3.05 inches above the yearly average); this amount does not include 56-5 inches of snow, which is measured quite separately from rain.

An important step for the promotion of New South Wales meteorology is recorded in the C.S. Monthly Weather Review (vol. xxxii., No. 11, p. 518). It seems that the principal newspaper of the colony, the Daily Telegraph, has commenced the publication of a daily weather chart. The origin of this step is stated in the following brief extract from the first number of the paper which contained this new information, a more complete account of which is inserted in the Weather Review referred to above :-" The inclusion of meteorology in the new public schools syllabus has directed special attention to consideration of weather conditions. Correspondents,

including a number of public school teachers, have applied FIG. 1.- View of the Cullinan Diamond. Actual size. From a photograph to the Daily Telegraph for amplified daily information on by E. H. V. Melvill.

this subject, and the meteorological branch of the Sydney

Observatory also has been requested to furnish details of diferent points of view. One of these pictures is here the weather conditions and atmospheric pressures, the inghen (Fig. 1), and it conveys a good idea of the size and formation upon which the weather forecasts are made. shape of the crystal. The stone is bounded by eight sur. The Daily Telegraph has arranged to publish daily a chart faces, four of which are faces of the original crystal, and showing the principal features of weather conditions, inLour arr cleavage surfaces, which are distinguished from cluding the high and low pressure isobars. Where possible the original octahedral faces by greater regularity and the rainfall area will be indicated and conditions on the stacothross. For a large stone the crystal is of remark- coast will also be given. ... The publication of isobaric abir purity, and the colour approaches that of a blue charts will enable students with their local knowledge of white. The complete crystal appears to have been a dis- physical surroundings to anticipate in detail their probable torted octahedron., with dodecahedral faces developed on weather more completely than is possible at the central

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42

as

a

office, where precise knowledge of local peculiarities is solution the authors have constructed a voltameter which lacking.” Those acquainted with Australian meteorology | is-according to their published results—more accurate will appreciate the importance of disseminating a know- than the copper coulombmeter, and does not fall far behind ledge of this valuable factor in Australian welfare. In the silver instrument. A glass beaker is used as the many countries the absence of public interest in the science electrolysing cell, and a kathode of thin lead sheet is hung of the weather is due to its omission from all school in- between two anodes of the same metal. The calculated struction, and we in Great Britain are suffering from the value of the electro-equivalent of lead is 103.46. In this same neglect.

instrument, in which the electrolyte was 8.5 per cent. The current number of the Fortnightly Review contains

PbSiF, 2.5 per cent. H,SiFs, and a small quantity of an article by Major B. Baden-Powell, president of the

gelatin, the numbers found in six experiments ranged from Aëronautical Society, entitled Air-ships and M. Santos 103.39 to 103.49. Among other papers of interest in the Dumont." Major Baden-Powell supplements and criticises

same journal we note the electrolysis of fused salts, by a contribution by M. Santos Dumont to an earlier number

Dr. Lorenz; the electrical extraction of nitrogen from the of the same review on air-ships. He also points out some

air, by Mr. J. S. Edström ; electrolysis and catalysis, by

Dr. W. Ostwald. of the advantages to be gained by flying machines not dependent on a light gas to lift them, and directs attention

The latest number of the Journal of the Russian Physical to a few of the drawbacks inherent in the large gas-bag.

and Chemical Society (1904, No. 9) contains the conclusion The attainment of human flight, he contends, apparently

of an

interesting study, by B. N. Menshútkin, on

Lomonósoff presents no insuperable difficulties. “ All that is wanted,

a chemist. natural philosopher and

Lomonósoff's services in the creation of the Russian so far as I can see, is a few thousand pounds and a clever and energetic inventor, and there is no reason why a

literary language and poetry are well known ; but the remachine could not be constructed within a year or two

markable work of this eighteenth century natural philocapable of rising and carrying a man in safety for, at all

sopher, of whom his friend and correspondent, Euler, events, a short trip through the air."

always spoke with great respect, had hitherto found no

proper appreciation in his mother country. His ideas upon THE water jet affords a most convenient method of

the structure of matter, the atomistic theory of chemical applying the power carried by high-pressure water, whether

changes, the mechanical theory of heat, his kinetic theory for driving wheels, such as are generally known as Pelton

of gases, his views on the liquid and the solid state, and wheels, for conveying the water itself into burning build

his theory of atmospheric electricity, which, he said, is ings, or for the destructive process of breaking down a

always present in the atmosphere, and originates from the mountain side, as practised in hydraulic mining. All this

changes in the thermal potential of ascending and descendis especially the case in mountainous country where water

ing air currents-all these theories being based upon supply with almost unlimited head is available. As it is

molecular movements within the bodies—were expressed in not always necessary that the jet should work at full

terms almost identical with those which are used now. power, regulation becomes necessary. Merely reducing the “ It is,” he wrote, the inner, unseen motions of the flow of water by throttling elsewhere than at the jet corpuscles of which all bodies are composed which are the would be ruinously wasteful, for half the flow would

cause of every rise of temperature in a given body. These carry one-quarter the

power,
and driven wheel

movements are rotatory. When a cold body is brought would no longer run at the proper speed.

into contact with a hot one, the latter communicates, to lating nozzle described in a thesis entitled

“ An In

the former the movements of its particles, which therefore vestigation of the Doble Needle Regulating Nozzle," by

are slackened in the hot body, and accelerated in the cold H. C. Crowell and G. C. D. Lenth (printed by permission

The greater these rotatory movements, the greater of the Civil Engineering Department of the Massachusetts

the repulsive forces, and the weaker the connection between Institute of Technology, Boston, and Tangential Water them. Wheels, Abner Doble Company), contains a spindle-shaped

Dr. A. C. HADDON, F.R.S., is delivering a course of concentric needle which may be advanced so as to reduce

lectures on Saturdays at the Horniman Museum, Forest the area of the orifice or withdrawn so as to enlarge it,

Hill, S.E., on Magic and Primitive Religion." but the form of the annular passage-way is always such as to lead the water to converge along easy stream lines,

The first volume, that for 1904, has been received of a until a circular jet of corresponding size is the result.

series of yearly publications to be issued by the Chemical In this way a range of 10 to 1 in the area of the jet may

Society under the title Annual Reports on the Progress be attained, while the full head is always available. Very

of Chemistry." The object of these reports is to pre-ent beautiful photographs are given showing the jets like clear

an epitome of the principal definite steps in advance which glass rods instead of the familiar opaque and spray-clothed

have been accomplished in the preceding year. The firs stream of water. Efficiencies from 96.4 to 99.3 for the

volume contains articles on general and physical chemistry. energy of the jet are found, which correspond to 98.2 to

by Prof. James Walker, F.R.S.; on inorganic chemistry,

by Dr. P. P. Bedson ; on the aliphatic division of organi 99.7 for the velocity.

chemistry, by Mr. H. J. H. Fenton, F.R.S. ; on thIN vol. vi. of the Transactions of the American Electro- aromatic and other cyclic divisions of organic chemistry, bu chemical Society, which has just been published, Messrs. Prof. J. B. Cohen; on stereochemistry, by Prof. W. J. A. G. Betts and E. F. Kern publish a paper on the “ lead

Pope, F.R.S.; on analytical chemistry, by Mr. A. C voltameter.” Two years ago Mr. Betts found that lead

Chapman; on physiological chemistry, by Prof. W. D) could be deposited in a non-crystalline and dense form from Halliburton, E.R.S. ; on agricultural chemistry and vege solutions of lead fluosilicate to which had been added a table physiology, by Dr. J. A. Voelcker ; on mineralogica' small quantity of gelatin. The Canadian Smelting Com-chemistry, by Dr. A. Hutchison ; and on radio-activity, bu pany now manufactures more than twenty tons a day of Mr. F. Soddy. These summaries of the chief advances in refined lead from solutions of lead silicofluoride. Until various branches of chemical science should prove of red Mr. Betts discovered this process it had not been found benefit to students, teachers of chemistry, and professional possible to refine lead electrolytically. By using the above chemists.

a

The regu.

one.

20 .. 10

ionisation of the solar atmosphere resulting, as Lenard OUR ASTRONOMICAL COLUMN.

has shown, from the action of the sun's strong ultraEPHEMERES FOR COMET 1905 a.-A set of elements and a violet radiation. By a simple calculation Prof. Arrhenius daily ephemeris for comet 1905 a are given in No. 4011 of

shows that the remaining positive charge is balanced, and the Astronomische Nachrichten. The ephemeris has been

the balance maintained, by the attraction of negative computed by Herr M. Ebell, and an extract is given

electrons emitted by other celestial bodies which are below:

negatively charged and lose their charge under the in

fluence of their ultra-violet rays. All such rays coming Ephemeris 12h. (M.T. Berlin).

within a mean distance of 0.063 light-years of the sun will 1903 (true) 3 (true) logo logs Bright

be attracted thereto, and by this means the supply of . m $.

ness negative electrons becomes just proportional to the defect May 12 ... 9.45 27 ... +49 15:8 ... O'1066 ... 9.9814 ... 0:42 thereof. 16 ... 10

8 56 .. +49 44'2 ... Oʻ1172 ... 0'0002 ... 0'36

31 29 ... +49 51'5 ... 0'1281 ... 0'0189 ... 0:32 VARIABILITY OF MINOR PLANET (15). EUNOMIA.-Circular 24 ... 10 52 58 ... +49 40'1 ... 0'1394 ... 0'0375 ... 0'28 No. 94 of the Harvard College Observatory is devoted to

28.11izil ... +49 13'1 .. 0:1508 ... 0'0558 ... 0 24 an account of Prof. Wendell's observations of the minor Tune I II 32 9... +48 32 8 ... 0:1623 ... 0'0740 .. O'21 planet Eunomia, from which he established a variation of S... I1 49 51 ... +47 418 ... 0'1739 .. o'ng19 ... 0'18 magnitude of about 0.5. The observations were made with

a photometer having achromatic prisms and attached to COMETS 1905 II (1904 e) and 1904 1.-A daily ephemeris the 15-inch telescope. As the planet was near its stationary far comet 1904 €, computed by Dr Strömgren, is given in point: it was compared with the same star, +13° 1875 No. 4011 of the Astronomische Nachrichten. The comet is (mag. 9.0), from March 15 to April 1, and the corrected Now try faint, and as seen by Dr. Palisa at the be differences varied from -0.77 to – 1:11. The formula ginning of April it was 10" in diameter, and had a four J.D. 2416920-116+0.1267 E. expresses the phase and period teenth-magnitude nucleus. During the present month it of the changes. The period is very similar to that found will apparently travel through the constellation Lynx in a for minor planet (7), Iris, viz. 0.1295d., and in both cases south-easterly direction towards Leo Minor.

it is still doubtful as to whether the period requires A bi-daily fphemeris for comet 1904 I, computed by doubling or not. Herren Nijland and van d Bilt, is given in the same journal. This comet is also faint, being 0.052 as bright FAINTNESS OF PLANETARY NEBULÆ. Some interesting as when first discovered, its magnitude then being about

results of calculations appertaining to the luminosity of 90. It is likewise situated in the constellation Lynx, and the surfaces of several planetary nebula. as como is apparently travelling in a S.S.E. direction towards the surface luminosity of the sụn or the moon, are given Cancer, although at the beginning of September it will

in a letter written by Mr. J. E. Gore to the current number

of the Observatory. only be about 3° south of 35 Lyncis.

Dealing with the nebula H, iv. 37, situated near to the OBSERVATIONS OF JUPITER.The results of their observ- | pole of the ecliptic, he finds that the ratio of its surface ations of Jupiter during the 1904-5 opposition are given luminosity is to that of the sun's as 1 : 43196.7 x 10°. The by MM. Flammarion and Benoit in the May number of similar ratios for the nebulæ h 3365, 3 5, and G.C. 7027 the Bulletin de la Société astronomique de France. are 1:2453 X 10", 1: 1095.5 X 10", and 1:434 X 10oreNumerous points of change in the colours and forms of the spectively; thus the brightest of them, i.e. h 3365, has a various features are noted, and some of them are illus surface luminosity of only 1/400 that of the moon. trated on the four drawings accompanying the article. Among the other conclusions derived from these observations the writers state the following :-(1) the estimations suf the coloration of the equatorial bands do not confirm

THE COWTHORPE OAK. Mr. Stanley Williams's views as to periodical changes

IN the Transactions and Proceedings of the Botanical therein : (2) the appearance of the Great Red Spot has

1 not changed since the previous opposition ; (3) the large

Society of Edinburgh (vol. xxii., part iii., 1904, p. 396) variation of the longitude of this feature between March

we notice a very interesting article on the Cowthorpe Oak and June, 1904. was probably due to the passage alongside

from the pen of Mr. John Clayton. This venerable tree, It of the dark region of the tropical zone ; (4) a clear spot

which stands near the church of Cowthorpe, a small situated in longitude oo of system ii., and dividing the

village near Wetherby, is unique among oaks in that its south equatorial band, appears to be a permanent feature

girth is greater than that of any other known tree of its which it will be well to observe assiduously. They further

species. Recorded measurements taken about 1700 show urge that careful attention should be paid at the end

that it had at that time a height of 80 feet with a girth of this year to observations of the movements of the red

of 78 feet on the ground. Since then various observers

have recorded its dimensions and noted at the same time spot, of the bright spots on the southern edge of south

the gradual process of decay, damage by storm, and other temperate band announced by Mr. Denning, and of the dark region situated in the south tropical zone.

points likely to be of interest. The latest measurements

were taken by Mr. Clayton himself, and they show that THE ELECTRIC CHARGE OF THE SUN.-In No. 1, vol. X., the height is now reduced to 37 feet including dead wood, of Terrestrial Magnetism and Atmospheric Electricity is re while the girth on the ground has diminished to 54 feet printed the address “ On the Electric Charge of the Sun". 3 inches. In 1893 a crop of acorns was produced, from delivered by Prof. Svante Arrhenius before the International one of which a seedling was reared, and is now planted Electrical Congress held at St. Louis last September.

near its parent as a memorial. After briefly discussing the various theories regarding The tree stands in a warm, sheltered spot in a field the nature of the sun's repulsive action, the author shows which has a gentle slope to the river, and near enough to that the theory which explains the phenomena, by pre get a constant supply of water. The process of decay has mising that the repulsion is due to radiation pressure been going on for the last 200 years. Between 1703 and acting on negatively charged particles, is in accordance with 1722 much damage was done by various storms; neverobservational records. The particles having a specific theless, new leaves are put forth annually. The acorns weight of 1.0 and a radius of 0.08 u are those which are produced in 1893 were on long stalks-hence the species repelled at the greatest speed, and would reach our atmo is Quercus pedunculata. As regards the age of this giant sphere in about 45.9 hours, an interval of the same order | opinion seems to differ. The trunk, being now hollow, as that obtained by Riccò for the time intervening between precludes all possibility of ever ascertaining the number the probably correlated soiar and terrestrial phenomena. of year-rings, and no trustworthy data are available before These particles are negatively charged in accordance with the year 1700—hence the author has been compelled to Mr. C. T. R. Wilson's proof that such particles are more rely upon a comparison with the age of other trees. In easily condensed on negative than on positive ions, the a tree the duration of life may be taken as composed of

three periods, one of growth, one of maturity, and lastly sacred edifice, such as this yew and the Cowthorpe Oak, one of decline and decay. Between the number of years and the association no doubt affords them protection. in each period a certain ratio is found to exist, and, taking Another notable veteran is the great chestnut of Tortthis as a basis, together with what is known of the tree worth, Gloucester, which girths 49 feet 2 inches at 4 feet since 1700, Mr. Clayton arrives at the conclusion that its from the ground. It also stands about 100 yards from a age is not more than 500 years—certainly much nearer very old and beautiful church. the mark than the age of 1600 years assigned to it by As regards the longevity of trees, the theory was proProf. Burnett in 1842, who based his calculation on the mulgated at the beginning of the nineteenth century by theory of the elder De Candolle that a tree increases by De Candolle that the duration of life in trees was pracone-twelfth of an inch in diameter annually, an altogethertically unlimited, neglecting accidents due to unfavourable untrustworthy basis of calculation.

external conditions, such as the ravages of parasites, There is quite a number of other interesting historical injuries from storms, lightning, and other causes. Passtrees dealt with in the article, for example, the Greendale ing in review the vegetable kingdom, we find there are Oak in Welbeck Park, which belongs to the Duke of some lowly organised plants, such as certain alga and Portland. Its height was recorded by John Evelyn in fungi, the whole life cycle of which may be completed 1846 as 88 feet, while the altitude of the highest twig at within the short space of a few days, or even hours. the present day is only 54 feet. In 1724 a roadway was Among the higher plants we have annuals and biennials cut through the trunk, which girths 30 feet 1 inch at the existence of which terminates with the production of 4) feet from the ground. The height of the archway was seed. Then we have the agave and certain palms, the

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There is a

Cowthorpe Oak, seen from North. The tree is supported by twenty-five props, disposed mostly on the South and East sides.

paling about 5 ft. high, which seems as if it had been put up from twenty to forty years ago.

then 10 feet 2 inches, but recent measurements show that aërial portions of which may live from ten to forty years the highest point is now only 9 feet 3 inches, and the until the production of flower and fruit terminates their lowest 8 feet 6 inches. This shows conclusively that a span of life, their place being taken by new aërial porsubsidence of the trunk must have taken place within the tions developed from lateral buds at the base of the plant. last 200 years, and, by assuming that a similar sinking In the case of trees and woody shrubs, on the other hand, into the ground has occurred in the case of the Cowthorpe new growing points are formed annually, but this vegeOak, Mr. Clayton explains the apparent discrepancies tative process does not end in the production of flower and between the earliest and latest recorded girth dimensions fruit, so that, excluding accidents, there is no reason why of the veteran. The trunk being somewhat tapering, the that vegetative process should not be continued for an diameter naturally lessens as the sinking in proceeds. Mr. unlimited time. Clayton adds a note on the testimony of a Cowthorpe man The giant Wellingtonias of California are well known named Oates, who said, “ The tree has shrunk very much examples of the age and dimensions which trees may in my time, and in shrinking the tree has twisted—the attain. A stem in the British Museum shows 1330 year. Eastern branches towards the South."

rings with a diameter of about 15 feet. On the other Another notable tree as regards size and age is the hand, certain Japanese dwarf trees are known to be of very Crowhurst Yew, which girths 34 feet 4 inches on the great antiquity, although lacking the size of the Wellingground. It stands in the churchyard of that place. The tonias. At the same time, one must not lose sight of the church must be very old, as it contains monuments of fact that the living cells are continually being renewed, and Saxon and Norman workmanship. The author points out that in a tree like the Cowthorpe Oak the living parts that the oldest trees are usually in close proximity to a : are at most but a few years old.

FISHERY INVESTIGATIONS IN THE

It must therefore, he continues, “ be supposed that as cod

and herrings, to a certain extent, depend upon contrary NORWEGIAN FJORDS.

current phases, a particularly good spring herring fishery DR. NORDGAARD has collected the results of investi- | would prevent a correspondingly good cod fishery in the

gations made in some of the fjords of northern same district; for a strong tendency of the upper layers Norway in the winters of 1899 and 1900, during the course towards the coast certainly takes herrings along in the of researches in the fishing waters of Lofoten, carried out current, but this at the same time causes a compensation at the expense of the Bergen Museum and the Norwegian current in the deep water, and this current hinders the Government. Two " expeditions" were made. The first, cod in its passage to the spawning places." January to May, 1899, included the Vest Fjord and the The statistics of the yield of the cod and herring sea beyond Lofoten, Vesteraalen, Sengen, and Finmarken, fisheries for some years are discussed and compared with Besides a large number of fjords, as the Kirk, the Øgs, corresponding values of rainfall, with results which appear the Kanstad, the Sag, and many others. The second, in to support the hypothesis brought forward. It would of the winter of 1900, was made so as to obtain material course be easy to suggest difficulties, such as the exfrom the fishing banks which would compare with that of tension of the current régime observed in fjords to areas the previous year, and it included visits to the Morsdal, which can hardly be regarded as such, and may thereSalten, Skjerstad, and Folden fjords.

fore have a different system of movements. But as The hydrographical observations, which are numerous, the whole question is at present under investigation on the have been made according to recognised standard methods, large scale by the International Council, we content ourand are therefore comparable with observations made selves with an attempt to summarise Dr. Nordgaard's further out at sea, in the regions in which the full ex- results, deferring fuller discussion of them until the more planation of many of the facts brought to light here is abundant data are available. doubtless to be found. The chief hydrographical result arrived at by Dr. Nordgaard is that the northern fjords can be divided into two groups, those in which the bottom temperature is 6° C. to 7° C., and salinity about 35 pro

A NEW SLIDE RULE. mulle, and those in which the bottom temperature is below PC, and salinity less than 35 pro mille." As examples of M ESSRS. JOHN DAVIS AND SON, of Derby. the the former, the Salten, Folden, Tys, Ofot, and Vest fjords

1 well known instrument makers, are bringing out a are given, and as examples of the latter the Malang,

variation of the slide rule which is likely to increase its Lyngen, Kvaenang, Porsanger, Tana, Varaanger, Skjer

value for certain classes of calculation without interfering stad, Skjamen. Kanstad, Øgs, and Kirk fjords. It is

with the simplicity and convenience of the form with which suggested that while in some cases, as the Skjerstad

we are all familiar. The lower groove on the outside of fjord, the inflow of ocean water is cut off by a submarine

the rule, which ordinarily is only wide enough to hold ridge, the occurrence of the two typical groups may be

the inturned edge of the cursor, is made wider, so as to accounted for by the distribution of rainfall. The heavy

take one of the tongues of a spare slide, and this slide winter rainfall in western Norway affords a large supply

is held in place when required by two light aluminium of fresh water to the surface layers of the fjords, which

clips which grasp the ends of the rule and of the spare accordingly remain specifically light, notwithstanding the

slide while leaving the usual slide free to move. An Call of temperature. In northern Norway the rainfall is

extra cursor is also provided which is long enough to much less, bence the surface waters retain a high salinity,

grasp both the rule and the extra slide. By this means and as their temperature falls they sink to considerable any rare or special scales upon the extra slide are for the depths.

time being equivalent to scales upon the rule, and these Dr. Nordgaard also discusses at some length the vary. may be read against scales upon the other slide by means ing influence of different amounts of rainfall on the currents

of the long cursor. If desired, the extra slide can take within the fjords. Heavy rainfalls, which raise the sur

the place of the ordinary slide, or may be removed lace level of the water, are for the most part the result

altogether when the rule, if provided with an ordinary of winds from the ocean, which produce a similar effect;

cursor adapted to the altered lower groove, becomes an it is difficult to separate the effeots of the two causes, but

ordinary slide rule. In the example submitted, the extra a rainfall above the average is taken as a fairly certain

slide carries what are called E and - Escales. The E index of abnormal strength in the oceanic streams.

scale is a log log scale, and is always being re-invented ; In the " biological notes " which accompany the tables

it was called a P line or power line by Lieut. Thomson, a number of points are brought out showing and defining

who showed it at the Inventions Exhibition, and it was the connection between fauna and hydrography. It is

long before invented by Dr. Roget. This P or E line is show that whereas in the first or warm-water group of

very handy, for it at once enables the logarithm of any fjards the deep-water fauna is chiefly boreal, in the second

number on any scale, i.e. to any base, to be read accordgroup, where cold water of lower salinity makes its way

ing to its position against an ordinary A line, while fracdownwards, the predominant forms are Arctic. The effect |

tional or high powers of numbers are read with equal of the increased precision of modern methods of investi

facility. Compound interest, pressures and volumes of gation in greatly reducing the number of so-called cosmo

gases under isothermal or adiabatic conditions are readily politan species is also emphasised.

evaluated with the aid of the E line read against an A line. . The section of this memoir which deals with fisheries

If, however, a pair of E slides are used, one in the usual is specially important and suggestive. In discussing the

position and one attached below the rule by means of the Lofoten fisheries, Dr. Nordgaard adopts the view that the

clips, then against any value, say of v, on one, the cursor currents in the Norwegian Sea are controlled by the

will show the value of vy on the other, y having any winds, and that, as already explained, abnormal move desired value according to the relative position of the two ments of the currents off-shore or on-shore can be associ

slides. ated with rainfall above or below the average. Again,

The slide rules made by Messrs. Davis and Son are too he says, ** It is clear that during the movements to or well known for their accuracy and finish for it to be from the coast of the surface water. a compensating current necessary to refer more to such points, but by some curious must be set in motion in the deep water; it has long been

perversity or accident there is one little fault in the rule a recognised phenomenon in the fjords, that the surface

sent for examination which only needs to be pointed out and under currents go in contrary directions." From an

to be put right. On the feather edge a scale of inches in mamination of the observations, Dr. Nordgaard concludes

16ths is provided ; on the lower face outside the rule there rhat burrings move coastwards specially in the surface

is no scale at all, while inside, to be used like a hat layers, while the cod travels along in the deeper layers.

measure, there is a scale of millimetres beginning at 550.

If, therefore, the rule is required for the prosaic but very I Bergens Museum. "Hydrographical and Biological Investigations in Xorwegian Fjords. By O Nordgaard. “The Protist Plankton and the

useful purpose of measuring a length, this can only be Diatas in Bottom Samples." By E. Jørgensen. Pp 254 ; with 2r plates

measured in inches if it is 20 inches or less, or in milli2od s figures in the text. (Bergen : John Grieg, 1905.)

metres if it lies between 550 and 1040 millimetres. If,

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