894 PROF. W. H. MILLER ON THE CONSTRUCTION OF THE NEW STANDARD POUND. 
W nght of the Kilogramme type laiton. 
This kilogramme of brass, which will be designated by the letter JL, is deposited in 
the Ministere de ITnterieure in Paris, and serves as a standard for the purpose of 
adjusting the kilogrammes used in commerce. In a paper in the ‘Memorie di Mate- 
rnatica e di Fisica della Societa Italiana delle Scienze residente in Modena,’ t. xxv. 
p. 1, it is stated that in 1850, 9iii:L+89‘5 milligrammes in air (^= 18*90, 6=763*80). 
A bi ■ass kilogramme marked No. IV., the volume of which is assumed to be equal to 
that of £. (the grounds for this assumption are not stated), was weighed in water at 
16*97- The absolute weight of the water displaced by it was 124*5536 grammes. 
Hence i;IL assumed = ^;Kilo. No. IV.= volume of 124*590 grammes = volume of 
1922*720 grains of water at its maximum density. 730*078, 1^(20=20*933. 
Therefore ^91=751*011. The volume of 89*5 milligrammes or 1*38120 grain of pla- 
tinum = volume of 0*065 grain of water. Therefore f(91— 89*5 milligr.) =750*946. 
During the comparison, S. displaced 2*32768 grains of air, and 91 displaced 0*90868 
grain. Therefore £=91+0*03780 grain. L displaces 2*30493 grains, and 91 dis- 
places 0*89981 grain of air (log A=7‘07832— 10). Therefore 11:2:91—1*36732 grain 
in air (log A=7*07832— 10). 
The commercial standard lb. is a weight of 7000 grains, of the same density as the 
lost standard troy pound U. Denoting the commercial standard lb. by W, and the 
platinum standard by I, in air (log A=7‘07832— 10) W:0: 1 — 0*63407 grain. There- 
. 15432-34874 15432-34874 . , ^ 15432-349 _ . . 
fore — Wit — I— 1*39/88 grain. v%—v — — I = volume of 
7000 
7000 
7000 
29*599 grains of water of maximum density = volume of 0*03547 grain of air. There- 
fore ^ + 0*03547 grains 
15432-34874 
7000 
I. Hence £ ^ 
15432-34386 
7000 
W, in air, for which 
log A=7’07832— 10. £ appears to weigh 15432*344 grains, of which W contains 
7000. W appears to weigh 453*59278 grammes, of which £ contains 1000. 
Received June 7, — Read June 12, 1856. 
The Quartz Pound. 
The hardness of quartz, its capability of receiving a high polish, the absence of 
any hygroscopic properties, and its indestructibility at the ordinary temperature of 
the atmosphere by any chemical agent except hydrofluoric acid, are such valuable 
qualities in a substance used for the construction of weights, that Professor Steinheil 
was induced to adopt it as the material for a copy of the kilogramme. The only 
objection to the use of a weight made of quartz is, that on account of the large amount 
of air displaced, the barometer and thermometer must be observed with extreme care 
during its comparison with a weight of any ordinary metal. Notwithstanding this 
disadvantage, it appeared desirable to the Committee that a weight of quartz should 
be constructed sufficiently near 7000 grains to admit of readily deducing the pound 
from it. They accordingly commissioned Mr. Barrow to construct a weight of 
