20 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



very possibly produce a sensible effect upon the earth ; 

 whether it does or not is a question which can be settled 

 only by a careful and systematic investigation of the facts." 



The detailed reports of the various parties sent out by the 

 Naval Observatory have not yet been printed. The follow- 

 ing abstract of their principal work is taken from the Re- 

 port of the Secretary of the Navy for 1878. 



It was seen that in order to obtain thoroughly satisfactory 

 photographs of the corona, it would be necessary to use far 

 more powerful apparatus than had been employed hereto- 

 fore, and it was proposed by Professor Harkness to con- 

 struct two equatorial cameras of six inches aperture and 

 thirty-six inches focus. This plan was adopted, the objec- 

 tives being furnished by Dallmeyer, of London. Two of 

 the Tran sit- of- Venus 5-inch telescopes were removed from 

 their equatorial mountings, and the cameras were substi- 

 tuted in their places. In this way two very serviceable in- 

 struments were obtained which were subsequently used by 

 the parties of Professors Hall and Harkness. It was finally 

 decided to adopt dry plates, and Mr. Jos. A. Rogers kindly 

 furnished the observatory with some of his own manufact- 

 ure. The results subsequently obtained with them upon the 

 corona prove that there is every reason to be thankful that 

 his generous offer was accepted. 



As the liberal appropriation made by Congress enabled 

 the observatory to fit out quite a number of parties, the 

 co-operation of all the best-known astronomers in the coun- 

 try was solicited, and they responded heartily. While the 

 observatory was able to assist them both pecuniarily and by 

 the loan of instruments, they were left entirely free to plan 

 their own observations; thus securing; a wide rano-e of in- 

 vestigation. The final arrangement of the parties, and the 

 work accomplished by each, were briefly as follows : 



The party under charge of Professor Hall was stationed 

 at La Junta, Col. The principal results of the work of this 

 party were : 



1. Professor Hall made an unsuccessful search for Vulcan 

 with a 5-inch Chirk equatorial, magnifying power one hun- 

 dred and fifty diameters. The space south of and following 

 the sun was swept over, keeping near the ecliptic and sweep- 

 ing about 10 east of the sun. 



