57 
vey. These are referred to in the report, lettered F, of 
Committee No. 8. This report contains also the results of 
experiments on iron vessels in the course of construction, 
and of iron-turreted vessels, especially of the three-turreted 
iron-clad, the Roanoke, and of the monitor Passaic. The 
five compasses of the Roanoke were compared near New- 
port News, by swinging the vessel and noting the deviation 
at different points. With this report are presented nine 
sub-reports, as follows : — 
No. 1. List of Iron-clad Vessels in Commission or Con- 
struction, as also of Iron Vessels not armored, either pur- 
chased, constructed, or being constructed. 
No. 2. Report of Professor F. Rogers on or on 
U. S. Steamer Ticonderoga. > 
No. 3. Report of Mr. A. D. Frye. 
Nos. 4, 5, 6,7. Report by Charles A. Schott, Assistant U. 
S. Coast Survey, Magnetic Survey of Roanoke and Passaic. 
No. 8. Drawings and Specifications of Ritchie’s Fluid 
Compass.* 
No. 9. Drawings and Specifications of Schott’s ——- 
Arrangement. 
A Committee, No. 4, on Mr. Saxton’s Alcoholometer, was 
appointed, as follows: Professor Frazer, Chairman, Doctor 
Barnard, Professor Chauvenet, and General Totten. Pro- 
fessor W. B. Rogers was also appointed, but declined. The 
report, lettered G, is herewith presented. It gives a lucid 
description of the instrument, which was itself presented to: 
the examination of the members of the Academy, and con- 
cludes, after a candid examination of its advantages and de- 
fects, by recommending its use to the government in place of 
the Tralles hydrometer, which is now employed in the col- 
* Omitted i request of Mr. Ritchie, communicated through Ad- 
miral C, * 1 
