26o NATIONAL ACADEMY OF SCIENCES 



cessful execution the various operations necessary for photographing the transit 

 of Venus by the methods decided upon by the commission, and of instructing the 

 parties in those operations. Dr. Draper accepted this arduous duty, and per- 

 formed it in a manner which commands the gratitude and respect of the com- 

 mission. Dr. Draper declined to receive any compensation or reimbursement for 

 his invaluable services and for his unavoidable personal expenses while traveling 

 and residing in Washington, on the service of the commission. 



" The system of practice was fully carried out, and the several parties destined 

 for the observation of the transit of Venus in both hemispheres, left the United 

 States fully qualified in all respects to perform their duties. 



" Instructions for conducting the scientific operations of the parties were pre- 

 pared by Professor Newcomb, printed, and freely distributed." ^^ 



The Transit of Venus Commission of 1874, which was con- 

 sidered as having continued in existence, took charge of the 

 arrangements for the observations of the transit of 1882 and 

 prepared instructions to the observers that w^ere printed by 

 authority of the Secretary of the Navy.'^ The Secretary remarks 

 as follows in his report for the fiscal year ending June 30, 1882 : 



" Transit of Venus 



" Professor Harkness has been principally occupied in fitting out the parties for 

 observing the approaching Transit of Venus, and in reducing the zone observations 

 made in Chili during the years 1850, 1851, and 1852, by the astronomical expe- 

 dition to the southern hemisphere, under the late Capt. James \l. Gilliss 



" Everything relating to the organization of the Transit of Venus parties is 

 confided by law to the Transit of Venus Commission ; but as most of the executive 

 work has been done at the Observatory, it may be proper to refer to it here. 



" The instruments used for the last Transit have been e.xamined and repaired; 

 all necessary changes have been made in them, and some new instruments have 

 been purchased. 



" At a very early stage of its deliberations the Commission decided to rely 

 mainly upon the photographic method of observing, and, to ascertain the most 

 suitable kind of emulsion, an extensive series of experiments was made by Mr. 

 Joseph A. Rogers, who has also prepared all the emulsion needed for the various 

 parties. 



"Rep. Seer. Navy for 1874, pp. 68-69. 



'"Instructions for observing tlie Tr.-insit of Venus, December 6, 1882, prepared by the 

 Commission authorized by Congress, and printed for the use of the observing parties by 

 authority of the Hon. Secretary of the Navy. Washington, 1882. 4°. Pp. 1-50, with 

 4 charts. 



