842 



SCIENCE. 



[N. S. Vol. VIII. No. 207. 



operation with other nations and laid the 

 foundation for what was called the middle 

 European ' Gradmessung.' These limits 

 held until 1867 when the word 'middle' 

 was dropped and the Association was en- 

 larged to comprise representatives from all 

 Europe. The extension seemed for a time 

 to satisfy the energy everywhere manifest, 

 but the fact soon became apparent that the 

 work fell short of its full usefulness in that 

 its bounds of activity were still too re- 

 stricted. Perhaps the gigantic strides made 

 by America and Australia in mental and 

 material development had something to do 

 with the change. At any rate, in 1886, the 

 name was again changed ; this time from 

 the European ' Gradmessung' to the inter- 

 national ' Erdmessung.' A convention was 

 drawn up for ten years. The powers of the 

 League were considerably enlarged, old fet- 

 ters were broken, and for the first time the 

 Association reached its highest plane of 

 usefulness and began to direct a homoge- 

 neous plan for the measurement of the 

 earth. 



The twelfth general conference was held 

 at Stuttgart from the 3d to the 1 2th of Oc- 

 tober, 1898. Fifteen countries of the nine- 

 teen composing the Association were rep- 

 resented. Of the thirty-seven delegates 

 present, fifteen came from Germany, five 

 from France, three from Italy, two from 

 Switzerland, two from Japan, and one each 

 from Belgium, England, The Netherlands, 

 Aubtria- Hungary, Russia, Sweden, Spain, 

 Mexico and the United States. Each gov- 

 ernment has the privilege of sending as 

 many delegates as it pleases, but in voting 

 on questions coming before the conference 

 for action but one ballot is allowed to each 

 country. Besides the delegates, eighteen 

 invited guests appeared, making a total of 

 fifty-five persons present at the meetings. 

 By far the greater part of the time was 

 naturally taken up in reading the regular 

 reports by the delegates on the geodetic 



work accomplished in their respective coun- 

 tries since the last general conference. Of 

 special interest was the contribution by 

 Professor Helmert on the activity of the 

 Central Bureau of the Association at Pots- 

 dam. The following work was described : 



I. The systematic deviations of the plumb 

 line in connection with the European arc 

 on the 52° of north latitude. 



II. The international latitude service. 



III. Absolute determinations of gravity. 

 Without going into details at this stage 



of our narrative, we may note in passing 

 one or two points brought out. The con- 

 nection between Switzerland and Italy is 

 now satisfactorily made. It rests, however, 

 on a single triangle, due to the fact that 

 one of the points composing the quadri- 

 lateral proposed was not occupied identic- 

 ally by the two surveys. 



The international latitude service will be 

 inaugurated during the summer of 1899 at 

 four stations under the direct control and 

 at the expense of the Association. Observa- 

 tions at two additional stations will be 

 undertaken, for which the Central Bureau 

 will supply onlj' a part of the funds neces- 

 sary. Although the mathematical condi- 

 tions are not essentially changed by the 

 introduction of Cincinnati and Tschardjui, 

 there is great advantage from the fact that 

 any systematic errors in the regular stations 

 will be more readily discovered. It is a 

 fortunate coincidence that the observatory 

 at Cincinnati happens to be precisely on 

 the parallel of latitude chosen for this work, 

 and it is, moreover, a matter for congratula- 

 tion that Russia is ready and willing to aid 

 in the undertaking, to the extent of estab- 

 lishing and superintending the station at 

 Tschardjui. 



The report also stated that in the abso- 

 lute gravity work measurement of the length 

 of the pendulum, the most difficult opera- 

 tion in the whole problem, can be effected 

 both in a horizontal and vertical position. 



