68 



NA rURE 



[May 28, 1874 



accurately known. The gro'ip of islands about Ker- 

 guelen's will depend very much upon the British observa- 

 tions of the moon ; but it will be well if chronometers 

 could be employed to connect it with the Cape. The 

 Germans rely very much upon the heliometric method. 

 It will be a matter of great interest to learn how these 

 observations agree with other methods as a guide to the 

 arrangements for 18S2. The expense of this expedition 

 is about 130,000 thalers, besides the expenses connected 

 with chronometric determinations. 



The organisation of the German expedition has been 

 entrusted almost wholly to Dr. Auwers, as secretary of 

 the commission. His contributions to the subject are of 

 great value, and the zeal with which he has superintended 

 the expeditions, even in the minutest details, cannot b3 

 overvalued. 



IV. The Russians are mainly employed in utilising the 

 Siberian stations. The actual places which have been 

 chosen from which to observe the transit are given in the 

 following list, in order from east to west. The numeral I 

 appended to a station means that there are good ob- 



servers, practised with the model, good equatorcals, and a 

 heliometer or photo-heliograph. The numeral 2 signifies 

 the same without hcliometers or photo-heliographs. When 

 the numeral 3 is appended, the observer has not practised 

 with the model, and employs a small telescope. The 

 stations are : — 



Yeddo 2 

 Port St. Alga 3 

 Nakhodka 2 

 Wladivostock I 

 Port Possiet I 

 Lake Hanka I 

 Chabarovka 2 

 Peking 2 



Blagowvschtchenska 2 

 Nertschinsk I 

 Xhita I 

 Kiachta I 

 Tomsk 3 



Tachkent i 

 Port Peroffski I 

 Fort Uralsk I 

 Orenburg 3 

 Aschura-deh i 

 Teheran 2 

 Nachitzevan 2 

 Erivan i 

 Tiflis 3 

 Taganrok 3 

 Kertch 2 

 lalta 2 

 Thebes 2 



Besides the c stations the following will bo utilised, but 

 the sun will be very low : at Kazan the sun's altitude will 



Equatorial of the Biitish Expedllion. 



be 8° or 10°, at Nicolaif it will be 6°, and at Charkof and 

 Odessa 5''' ; at Moscow it will be exactly on the horizon. 

 As to instruments, the Russians are employing 6-inch 

 and 4-inch equatoreals. Their heliometcrs are larger 

 than those of the Germans, having 4 in. apertures. 

 Their photo-heliographs are constructed on the English 

 model by Mr. Dallmeycr. The telegraphic connections 

 between the stations have been already discussed. The 

 expense incurred will be defrayed by the Government. 

 Besides this, the State contributes 45,000 roubles. This 

 will be spent mainly on the transport and maintenance of 

 observers and instruments. The different observatories 

 in Russia have shared the expense of providing the dif- 

 ferent instruments. The whole expedition has been 1 

 conducted under the s.ipcrinten Jonco of M. Otto Struve. 



Some of the expeditions have already started provided 

 with every means for resisting the cold of a Siberian 

 winter. Great attention has been paid to the chances of 

 good weather. The accelerated ingress and retarded 

 egress will thus be admirably observed ; and the com- 

 parison which M. Struve has made with observers of other 

 countries in practising with the model will render com- 

 parisons possible. Moreover, many of the Russian 

 stations are admirably situated for the employment of 

 the method of durations ; and if the two internal con- 

 tacts be observed at any of the stations in the neighbour- 

 hood of Kerguelen's Island excellent results may bs 

 obtained. 



George Forbes 

 ( To be conliii -tea.) 



