804 PROF. W. H. MILLER ON THE CONSTRUCTION OF THE NEW STANDARD POUND. 
M displaces 0’81284 grain, T — 0’0415 grain displaces 0’32045 grain of air 
(^=18'28, 6 = 741'52). Hence M=T4-0‘4509 grain. AM = 8‘3491. 
In air(^=187, /;=755-64), M iiT— 0-04012 gr. But U— 0-0074 gr. There- 
fore M U - 0*0475 gr. 
In a letter from William Miller, Esq., of the Bank of B- Fig. 7. 
England, dated August 22, 1855, I was apprised of the 
existence at the Bank of a fourth troy pound of 1758, and 
soon afterwards received it from him with permission to 
weigh it in air and also in water. This weight (B) is a bad 
casting, though much better than O. The upright stroke of 
the 5 is left incomplete. The under surface is slightly con- 
cave, the depth of the concavity being about 0*01 inch. 
By one comparison, October 6, 1855, B :ii: (3200)4“ (1600) 
+ (800) 4- (100) (bronze) -f (32) + (16) 4- (8) 4- (4) 4- 0*271 
grain (platinum) in air (C=16‘0, F=746-3, E=16-4). 
B : 2 : 5699*9704 grains of bronze 4“ 60*2678 grains of plati- 
num in air (^= 16*03, 6 = 744*77)- 
By observations made October 2, 1855, B in water 
(K= 17'67) — (3200)-|-(1600)4-(200) (bronze) -}- (64)4- (4) -{- 0*2505 grain (platinum) 
in air (C=l7-0, F=754*55, E=l7-4). 
B in water (/= 17‘66) 4999*9640 grains of bronze 4-68*3459 grains of platinum 
in air (^= 17-05, 6 = 752*88). 
Hence e;B = 692*815, AB=8*3175, B = U4-0*2487 grain. B ^2= U4-0*2653 grain in 
air (^=18*7, 6=755*64). 
The magnitude of the differences between these weights is very remarkable, con- 
sidering that O, M, B are in a state of very excellent preservation, V alone exhibiting 
traces of rough usage. 
Linear dimensions of the different weights in inches. 
U. V. O. M. B. 
Axis 2-576 2-57 2-568 2-538 2-564 
Diameter of knob... 1-012 0-98 0-973 1-020 1-024 
Diameter of neck ... 0-359 0-383 0-391 
Diameter at d 1-43 1-416 1-391 1-387 
Diameter at e 1-445 1-43 1-424 1-389 
Diameter at/ 1-434 1-385 1-377 
The above comparison shows that the linear dimensions of U were very sensibly 
larger than those of M or B, and so far justifies the assumption that the volume of 
U was larger than that of M or B, probably not less than that of V ; for it cannot be 
supposed that the weight selected as the standard was a bad and porous casting 
like O, the linear dimensions of which are nearly equal to those of V, though its 
volume is considerably less in consequence of the numerous cavities that exist in it 
communicating with its surface. 
