to Geodetical and Astronomical pwposes. 53 



experiment was repeatedly performed that year by Mr. Walker, 

 assisted at Philadelphia by Prof. E. O. Kendall, Director, and at 

 Jersey city by Prof. E. Loomis. 



In July and August 1848, an extensive series of star-signals 

 and clock-signals, by coincidences, were exchanged between the 

 Harvard Observatory at Cambridge, Mass. and the observatory 

 in the garden of the late Peter Stuyvesant in Ts^ew York city. 

 The work was under the charge of Mr. Walker, assisted re- 

 spectively by Wilham Crouch Bond, Esq., Director of the Ob- 

 servatory at Cambridge, and Prof. E. Loomis at New York city. 

 During these experiments, Mr. Bond conceived the idea of using 

 an automatic circuit interrupter, and on the recommendation of 

 Mr. W^alker, received in July 1848, an order from Prof. Bache, 

 superintendent, for the construction of a clock for this purpose 

 in conformity with Mr. Bond^s di-awings, then before the superin- 

 tendent, t nx.>)3d &f»>inf>£ff) 



This clock was completed in 1850, and forms part of the ap- 

 paratus in use at Cambridge in 1850 and 1851. The work of 

 1848, in July and August, forms the date of the first connexion 

 of Mr. Bond and his two sons, Messrs. George P. and Richard 

 E. Bond, with the use of the magnetic telegraph line for longi- 

 tude, and with the machinery and apparatus for the same. It 

 preceded by two months the work between Philadelphia and 

 Cincinnati of the year 1848, when in the month of October the 

 attention of Prof. 0. M. Mitchell, and afterwards of Dr. John 

 Locke, was turned to the subject. The fact that Prof. Bache 

 had ordered an automatic circuit interrupter of Mr. Bond in the 

 preceding August, was communicated both to Prof. Mitchell and 

 Dr. Locke previous to their undertaking similar experiments. 

 , J On the 26th of October 1848, Prof. 0. M. Mitchell, at the sug> 

 gestion of Mr. Walker, prepared a circuit interrupter with an 

 ordinary eight-day clock, and used it to graduate the running 

 fillets of paper for several days. 



It was not used in the work with Philadelphia, clouds having 

 prevented work on the 27th, proposed for the purpose. The 

 same mode which Prof. Mitchell used had been proposed by 

 Joseph Saxton, Esq. in 1846, but has not been adopted by Prof. 

 Bache and Mr. Walker, from apprehension of injury to the per- 

 formance of the astronomical clock which must be used for the 

 purpose. This apprehension we know by experience to have been 

 groundless. 



On the 26th of October 1848, Dr. J. Locke having stated his 

 objection to Mr. Bond's contrivance of a circuit interrupter, was 

 requested by Mr. Walker, on behalf of the superintendent, to 

 undertake experiments to obviate them. 



On the 17th of November 1848, Mr. Walker receiving notice 



