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Hann's dynamical theory, instead of Ferrel's The half second pendulum apparatus deconvectional theory of extra-tropical cy- signed by Dr. T. C. Mendenhall was used, clones, being adopted. All those regions with methods not before employed with whose precipitation is in large part de- short pendulums. They were swung at a pendent on extra-tropical cyclonic storms low air pressure (60 mm.), each swing lastwould under these conditions have an in- ing eight hours, and the successive swings creased annual rainfall; and the lakes of covering the entire interval between the first interior basins in temperate latitudes would and last time observations, usually fortyconsequently increase in volume. The eight hours. The two chronometers used winter rains of subtropical belts, such as the were rated by star observations made with northern Sahara, would extend further to- a portable transit in the meridian. The wards the equator, for the equatorward mi- flexure of the support was measured and gration of the tropical belt of high pressure correction applied. The results indicate in winter is essentially a result of the in- the entire elimination of errors due to diurcreased vigor of the circumpolar circulation nal irregularities of rate, and show that at such times; thus the formerly greater there was practically no wear of the agate rainfall indicated by the desert wadies might knife-edge. Determinations made at the be explained. The coincidence of greater base station (Washington) several times precipitation during the same epochs of time during the year show a range of only over the glaciated, the lacustrine and the .000,004 second in the mean period of the desert areas is, however, not yet independ- three pendulums, indicating a high permaently proved.

W. M. DAVIS. nency of period, and throwing some light HARVARD UNIVERSITY,

on the invariability of gravity. The aver

age time required per station was slightly GRAVITY MEASUREMENTS. *

over five days. RELATIVE measurements of the force of

Values of gravity for Washington degravity were made in 1894 by the U. S.

rived relatively from absolute determinaCoast and Geodetic Survey at twenty-six

tions made in various parts of the world show stations, mostly located along the thirty

a considerable discordance, the range being ninth parallel from the Atlantic coast to

from 980.047 to 980.285 dynes. The reUtah. Points were included on the Atlan

sults of the past season are based on a protic coast, Appalachian mountains, central

visional value adopted for Washington. As plains, Rocky mountains (including the they were carried out with the same instrusummit of Pike's Peak, 14,085 feet in alti

ments and uniform methods, it is probable tude), western plateaus, and the eroded

that their relative accuracy is much higher valleys of the Green and Grand rivers.

than that of many of the absolute measures.

The results are discussed principally in * Results of a Transcontinental Series of Gravity

connection with the question of reduction Measurements,' by G. R. Putman, read February 2,

to sea level, the distribution of the stations 1895, Philosophhical Society of Washington, Bulletin Vol. xiii.; preliminary results were presented before

with respect to an unusual variety of contithe National Academy of Sciences by Dr. Menden- nental conditions rendering the series valuball, November, 1894. Mr. G. K. Gilbert, of the U. able in this connection. This is an imporS. Geological Survey coöperated in this work by mak

tant question in the application of penduing a geological exami tion of the stations. His

lum observations to the geodetic problem conclusions and a discussion of the results in connection with the theory of isostasy are published in the

of the earth's figure, and involves the varisame Bulletin.

ous theories as to the condition of the

earth's crust. It has given rise to many all general continental elevations are comdiverse opinions, and the apparent anoma- pensated by a lack of density or other lies in the force of gravity have been so cause below sea level, but that local irregugreat with various methods of reduction as larities of surface are not so compensated, to necessitate the rejection of certain classes but are maintained by the partial rigidity of stations even in the most elaborate dis- of the earth's crust. The measure of this cussions, as those of Clarke and Helmert. lack of compensation will be the attracThree methods of reduction were applied to tion of a plain whose thickness is the differthese stations, and the effect of latitude was ence in elevation between the station and eliminated by comparison with a theoret- the average surrounding country. The latical formula based on Clarke's figure of the ter was estimated within an arbitrarily the earth. In each of these methods cor- adopted radius of 100 miles of each point, rection was made for the elevation above and the correction applied, positive for sea level and for topographical irregularities stations below the average and negative for near the station, and they differ only in the those above.* With this reduction all the allowance made for surface attraction, as large residuals disappear. For the fourfollows :

teen stations (in mountainous regions) 1. Bougner's reduction. The vertical at- where it was applied, the sums of the retraction of the entire mass above sea level siduals are: with Bougner's reduction 2.577 was subtracted. With this method the re- dynes, with elevation reduction 0.677 dynes, sults show a large defect of gravity on the with Faye's reduction 0.175 dynes, indicawestern mountains and plateaus, closely ting a decided advantage for the latter. proportional to the average elevation, but A similar discussion made of former having no relation to the altitude of the Coast and Geodetic Survey observations on particular point of observation or to dis- oceanic islands and coasts shows that the tance from the ocean.

excess of gravity that has been found on 2. Elevation reduction. No correction islands with Bougner's reduction largely was made for attraction. The defect of disappears on the application of Faye's idea, gravity in general disappears, but there are subtracting the attraction of islands conlarge residuals in the mountainous regions, sidered as displacing sea water. The residgravity being in excess at stations above uals with Bougner's reduction are probably the average level of the surrounding coun- a measure of the lack of density below sea try, and in defect at those below. The level, and with the elevation reduction a size of the residuals is nearly proportional to measure of the lack of compensation. The the difference in elevation between the sta- general conclusion is that the so-called tion and the average level.

anomalies of gravity may be largely ac3. Faye's reduction. On the theory that counted for on general principles, and that the surface of the earth is in general in a the value of these measurements in conneccondition corresponding to hydrostatic tion with the problems of geodesy and the equilibriun, M. Faye proposed that no cor- intimately related questions of terrestrial rection be made for the attraction of the physics will be proportionately enhanced. average mass above sea level, but that ac- By comparing the values of g measured count be taken of local deviations from the on the summit and near the base of Pike's average level, as, for instance, the attraction Peak the value 5.63 was deduced for the of a mountain on a station at its summit.

* Mr. Gibert independently applied this method Developing this idea we may consider that of reduction, using a radius of 30 miles.

mean density of the earth. The attraction etc., which formed the beginning of what of the mountain was computed from contour is now a very valuable library. Without maps and from information as to its density this very material aid the progress of the furnished by Mr. Whitman Cross of the U. Toronto Society would have been very slow S. Geological Survey. A set of quarter- indeed, but as, at meeting after meeting, the second pendulums designed by Dr. Menden- secretary's and librarian's reports were read, hall was tested at four of the stations with it became soon apparent that the heartiest satisfactory results. This is the smallest sympathy and support were being extended, apparatus yet made for the purpose, weigh- without exception, by all who had been ing but 106 pounds with packing boxes. addressed.

HERBERT G. OGDEN. The first annual report of the Society was WASHINGTON, D. C.

an unpretentious little volume of 40 pages,

containing abstracts of papers read during THE ASTRONOMICAL AND PHYSICAL SO- the year 1890, and records of the more imCIETY OF TORONTO.

portant work done at the telescope by the This Society, now very widely known, various members who were particularly inwas originally formed in 1884 by a few gen- terested in observation. The frontispiece tlemen who, while actively engaged in busi- was a drawing of sun-spots and also of ness pursuits, were kindred spirits in their hydrogen flames, by Mr. A. F. Miller, who love for scientific study and met at inter has always taken a keen interest in solar vals more or less regular at their respective physics. Mr. T. S. H. Shearmen contribresidences for recreative reading, observa- uted a paper on

uted a paper on 'Coronal Photography, in tion and experimentation. The member- the Absence of Eclipse.' In common with bership gradually increasing, it was finally many other enthusiastic observers, Mr. decided to secure incorporation under a Shearmen is still engaged upon this work. general Act permitting the acquiring and Referring to the objection raised regarding holding of real and personal property, etc., the impossibility of photographing the corand in 1890 the Society became a corporate ona in full sunshine on account of the very body. The first president of the new asso- slight difference between the intensities of ciation was the late Mr. Chas. Carpmael, the two lights, Mr. Shearmen cites obM. A., F. R. A. S., the Director of the To- servations of the inferior planets seen proronto Magnetic Observatory; the vice-presi- jected on the corona. dent was Mr. Andrew Elvins, who had The appendix to this volume contains indeed been the first to gather together the a list of the presents donated by the few friends who had formed the original various observatories and scientific bodnucleus, and who is still highly esteemed ies in the United States, and by Mr. and honored as the father of amateur as- John Goldie, of Galt, Ont., a life member tronomy in Toronto. A constitution mod- of the Society. The list of the Society's exeled upon that of the Astronomical Society changes increased very rapidly after the of the Pacific having been framed and by- publication of the first report. The vollaws adopted, a circular was addressed to ume for 1891 contained papers by Dr. J. many scientific societies and distinguished Morrison, Mr. J. Ellard Gore and Mr. W. astronomers and physicists throughout the F. Denning. An opera-glass section had world. Several of the latter became corre- been formed which met during the weeks sponding members, while various scientific alternating with the regular fortnightly bodies contributed many volumes of reports, meetings of the Society, and much interest began to be taken in active telescopic work. ology. The constitution was amended to An essay by Mr. G. E. Lumsden, entitled a admit of election of two vice-presidents, and * Plea for the Common Telescope' (subse- Dr. Larratt W. Smith, Q. C., and Mr. John quently reprinted in the Scientific American A. Paterson, M. A., were appointed. During Supplement), was the means of creating a this year also the Hon. G. W. Ross, LL.D., very general desire for the possession of in- Minister of Education, became Honorary struments of moderate aperture, and there President. The Society was now becoming are now a great many telescopes ranging to very extensively known, and its list of cor5-inch among the members of the Society. respondents rapidly increasing. The meetMr. Lumsden's own telescope is a 107-inch, ings were particularly well attended, and With-Browning reflector. It was with this the Toronto press was most courteous and that he made an observation of a double obliging in publishing reports of the Society's shadow of Sat. I in transit across the disc work from time to time.. Meetings were freof Jupiter, on the night of September 20, quently held at the Toronto observatory, 1891. The particulars of the observation where practical use was made of the large and comments upon theories accounting equatorial and other instruments of the for the possible cause of the phenomenon, equipment. The great magnetic storm of which has been seen but three or four February 13, 1892, was charted by Mr. F. times, appeared subsequently in L'Astrono- L. Blake, of the observing staff, and a phomie. A drawing of Jupiter made on the tographic reproduction accompanied the night of the observation forms the frontis- volume for that year. Towards the close piece to the volume of Transactions of the of 1892 a committee was appointed to act Society for 1891.

conjointly with a committee from the CanaDuring this year the Society lost a sin- dian Institute with a view to moving in the cere friend and earnest worker by the death matter of a change in astronomical time of the Hon. Sir Adam Wilson, Chief-Jus- reckoning. The report of the committee tice of Ontario. This distinguished jurist, was presented on April 21, 1893, and one of the most eminent of Canada's public adopted. It is now widely known that the men, had actively interested himself in great majority of astronomers are in favor scientific matters after retiring from the of reckoning the astronomical as the civil Chief-Justiceship, and had erected and day, from midnight to midnight, and it equipped an observatory at his residence. remains for the Government of the United Shortly after Sir Adam's decease, which was States to decide whether the ephemeris shall quite sudden, Lady Wilson donated to the be changed accordingly. The Admiralty in Society his telescope, a six-inch reflector, England has expressed a desire to meet together with other apparatus and many the views of other nations. works on science. Sir Adam had intimated During 1893 the Society was enabled to that he wished these to pass to the Society further the object always kept in view, the at his death. The reflector is now mounted popularizing of science, by the kindness of at the residence of Mr. John A. Paterson, the University authorities, who gave the use M. A., vice-president, and is used by the of the physical lecture room for popular members in regular observation.

lectures, illustrated by experiment. Mr. In 1892 McElvins resigned the office of C. A. Chant, B. A., and Mr. G. F. Hull, B. vice-president, in order to have more time A., have taken charge of this department at his disposal during which to take up of the Society's work with eminent success. active work on special lines, notably meteor- A very liberal interpretation of the physics


relating to astronomy having been made, Two of the members of the Society, there has resulted a keen interest in experi- Messrs. Z. M. and J. R. Collins, have been mental science; so that he is a welcome very successful in making silver-on-glass addition to the membership who takes in- specula, and have figured several of eightterest in any branch of what was formerly inch ; having recently fitted up apparatus styled natural philosophy.

for the work, it is confidently expected that During the years 1893 and 1894 the sub- they will soon be able to undertake the ject of magnetism and electricity engaged a construction of very large reflectors. It is large portion of the time spent at the reg- not too much to hope that they will be able to ular meetings. Spectroscopy, quite apart execute the telescope when the public spirit from its bearing upon astronomy, has also of the Toronto people demands a great obbeen a subject of interest. A valuable servatory, and this may be in the near note, by Mr. A. F. Miller, on the spectrum future, for, in regard to popularizing science, of the light emitted by insects, appeared in the Toronto Society has been eminently the volume of Transactions for 1893.

successful. A branch of the association at In the earlier years of the Society's ex- Meaford, Ont., has recently been formed, istence the meetings were held at the resi- and other similar societies are already dences of members, but it was ultimately spoken of.

THOMAS LINDSAY. found that one central place of meeting would be preferable, and for some time past

CORRESPONDENCE. the regular meetings have been held in the rooms of the Young Women's Christian TO THE EDITOR OF SCIENCE: Referring to Guild building. Here the library is kept a note on the Garden of Eden' in SCIENCE and the secretary has his office. The So- (May 3, 1895), I desire to point out that in ciety suffered another loss in October, 1894, a series of articles, under the heading Gold, by the death of the president, Mr. Carpmael, Bedolach and Shoham Stone,' in the "Exwhose health had been impaired for some positor' (London, 1887), I showed that the time previously. A short sketch of Mr. only possible scientific explanation of the Carpmael's very active life is appended to geography of Eden in Genesis is that based the Transactions for 1894.

on the geological explorations of Loftus, and Dr. Larratt W. Smith, Q. C., succeeded now advocated by Prof. Haupt, namely, that Mr. Carpmael in the presidential chair, and the four rivers are the Kherkhat, Karun, the office vacated by the former is now ably Tigris and Euphrates. Farther I showed filled by Dr. E. A. Meredith, formerly that the geography and geology of this Deputy Minister of the Interior, and the ancient anthor are more accurate than those predecessor of Sir Wm. Dawson in the of modern maps and popular statements presidential chair of McGill University, until within a very recent time, and that Montreal. The great work always before the local standpoint of the original writer the Astronomical and Physical Society of was on the Euphrates, and his date not Toronto is the founding of a popular ob- long after that of the historical deluge, servatory, in the true sense of the term; whatever views may be held by critics as to not being too sanguine, it is still hoped that the ultimate editing of the book. Delitsch steps will soon be taken to this end. It is and others have been misled by their want a matter of regret that there is no astro- of knowledge of the condition of the disnomical equipment in Canada able to meet trict in the earliest human (Palanthropic) all the requirements of modern astronomy. age, whereas this was evidently known

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