COMMITTEES ON BEHALF OF THE GOVERNMENT 233 



that the permanent marks should take the form of cast-iron 

 blocks coated with zinc. It was suggested to the Secretary of 

 War, however, that these blocks might be injured or destroyed as 

 a result of galvanic action between the two metals. He, there- 

 fore, requested through the Acting Quartermaster-General that 

 a committee of the Academy be appointed to advise him as to 

 the probability of such action in the metal headstones. 

 The letter was as follows : 39 



" QUARTERMASTER GENERAL'S OFFICE, 



" Washington, D. C., January 8, 1867. 



" SIR: It having been suggested to the War Department that the coating with 

 zinc of the iron head-blocks, with which it is proposed to mark soldiers' graves, 

 will produce galvanic action that will tend to a destruction of the iron blocks, the 

 Secretary of War has directed me to submit the subject to the Academy of 

 Sciences here, with a view to obtain an intelligent opinion on it, and to ascertain 

 if there be any good ground for the apprehension. 



" In obedience to this direction, I respectfully submit the subject to you with a 

 request that you will present it to the Academy of Sciences and advise me of their 

 opinion thereon, that I may make report thereof to the Secretary of War. 

 " I am, very respectfully, your obedient servant, 



" D. H. RUCKER, 

 " Acting Quartermaster General, Brevet Major General. 



" The PRESIDENT OF THE ACADEMY OF SCIENCES, Washington, D. C" 



A committee consisting of Joseph Henry, J. H. C. Coffin and 

 Joseph Saxton was appointed by the President on the same day. 

 It reported on January 17, as follows: 



" NATIONAL ACADEMY OF SCIENCES, 



" Washington, January 17, 1867. 



" SIR: In compliance with your request, the undersigned, a committee of the 

 National Academy, appointed to examine the proposed cast-iron head-blocks for 

 soldiers' graves, and state whether, in their opinion, the coating of zinc will tend 

 to produce a galvanic action destructive to the iron, respectfully report as follows : 



" The head-block submitted to the committee is a hollow truncated pyramid 

 of cast iron, on one side of which, in raised figures, is the No. 12,646, and on 

 the top, also in raised letters, the name of a soldier, his regiment, and a date, 

 probably that of his death. This block is entirely covered inside and out with 



119 Rep. Nat. Acad. Sci. for 1866, p. 17. Sen. Misc. Doc. no. 44, 4oth Congress, ist Session. 



