656 



SCIENCE. 



[Vol. II., No. 41. 



ordiiiates begin to change rather suddenly; but there 

 is no sign of a change before B. Shortly after B, I 

 still can conceive myself under the co-ordinates 

 formed on A B, by a mental effort. After about a 

 hundred yards the new co-ordinates have entirely 

 displaced the old. 



At the corner of 1.3th and Spring-Garden streets in 

 Philadi'lphia I had an experience like that of Profes- 

 sor Newcomb. For a long time I could not approach 

 the place, riding or walking, without my co-ordinates 

 changing by 90°. I cannotaccoimt for it. Gradually 

 it wore o&, and now no change takes place. 



Joseph Jastkow. 



Johns Hopkins universitj', Nov, 6. 



INTERNATIONAL GEODETIC ASSOCIA- 

 TION OF EUROPE. 



Verhandlungen der vom 11 bis zum 15 September 

 ISSS, im Haarj vereinigten permanenlen commission 

 der eurnpdischen gradmessung . Redigirt von A. 

 HiESCH und T. vox Oppolzer zugleioh mit 

 dem general bericht fur die jahre 1881 und 1882. 

 Berlin, iieimer, 1883. 6 -f- 155 p., 2 maps. 4°. 



The proceeding's of the annual meeting of 

 the committee at The Hague, Sept. 11 to 15, 

 1882, have just been published. The perma- 

 nent committee consists of the following mem- 

 bers : Lieut. -Gen. Ibaiiez of Madrid, president ; 

 Dr. von Bauernfeind, vice-president ; Dr. 

 Hirsch of Neuchatel, and Dr. von Oppolzer of 

 Vienna, secretaries ; Mr. Faye of Paris ; and 

 Major-Gen. Baulina of Florence. The dele- 

 gates, eleven in number, represent most of the 

 countries of Enrope. Some invited guests also 

 attended the meeting. The session was opened 

 \)j the minister of state, Rochusson of Hol- 

 land, who esteuded-to the members a cordial 

 welcome, which was responded to by President 

 Ibaiiez. 



The last meeting was held at Munich in 

 1880 ; but the commission resolved to omit 

 the contemplated meeting for 1881, in order 

 to give its members an opportunity to attend 

 the Geogxaphical congress at Venice : the 

 reports therefore submitted bj* the several rep- 

 resentatives cover the work done, or in active 

 progress, daring the two years 1881 and 1882. 

 Secretar}^ Hirsch alludes to the loss sustained 

 by the association since its last conference, in 

 the death of Dr. Carl Bruhns, a member of 

 the commission since 1864 ; in the death of 

 Gen. de Ricci, one of the veterans of Italian 

 geodesj' ; of Col. Adan of Belgium, and Pro- 

 fessor Stamkart of Holland. The latter had 

 shown that the mean level of the North Sea 

 had not changed during the past hundred and 

 fifty years with respect to the zero of the tide- 

 gauge at Amsterdam. And, last, the asso- 

 ciation had to mourn the loss of Professor 

 Plantamour of Geneva, whose labors in as- 



tronom3' and physical geography are so well 

 known, and to whose zeal the recent develop- 

 ments in levels of precision and the progress 

 made in pendulum observations are so largely 

 due. 



The Italian commission was increased by 

 Professor Fergola of Naples, by Professor 

 Celoria of Milan, and bj' Lieut. -Col. de Ste- 

 fanis of Florence. Austria nominated Capt. 

 von Kalmar and Professor Herr as commis- 

 sioners ; Holland completed its reprcsontation 

 bj' Professor Schols of Dolft ; and Roumania 

 sent Major Capitancanu. The honorary presi- 

 dent and founder of the association, IMajor- 

 Gen. Dr. Baej-er, who, on account of ill health, 

 was unable to attend, presented a report of 

 the labors of the Geodetic institute of Prussia 

 during 1881-82. He makes mention of the 

 success of the experiments ^ to determine the 

 difference of temperature between the bars of 

 platinum and brass of the Briinner base-appa- 

 ratus bj' means of thermo-electricity. Tlie re- 

 searches for local deflection of the vertical 

 were extended from tlie Ilarz to the shores of 

 the Baltic and the North Sea with the result 

 of proving it a region of predominating nega- 

 tive (A. — G.) deflection, varying between 4" 

 and 7". A list is presented of seventeen works 

 published by the institute during tlie interval. 

 Several of these relate to levels of precision ; 

 and the pamphlet by Dr. Sadebeck, entitled 

 ' Literature of the practical and theoretical 

 measurement of arcs,' deserves special men- 

 tion. In a discussion closing the first session, 

 relative to the proliable error in the assigned 

 length of the pendulum, it was stated, that, 

 to judge from the accord of the several swings, 

 it might be estimated at about one micron, 

 but that the oscillations of the pendulum sup- 

 port introduced a constant error, seriously' in- 

 fluencing the accuracy of the result ; the direct 

 measure of the motion of the support enter- 

 ing the result being only a fortieth of the 

 correction to pe applied. By this method the 

 accuracy is estimated at .01 mm. The propo- 

 sition by Cellerier to swing successive!}' on the 

 same stand two pendulums of the same form 

 and construction, but of very unequal weight, 

 promises complete success towards correcting 

 the defect in question ; and the experiment is 

 now being carried out. The second session 

 was chiefly occupied with the reading of re- 

 ports, and with a discussion respecting the- 

 value of the prismatic transit instrument.' Six 

 of these instruments emplo3'ed in the Italian 

 survey gave entire satisfaction, especially with 

 regard to perfection of their images. The dis- 



» Publisliecl In Aslronominche nachrichien, no. 2451. 



