Page:The British pharmacopœia.djvu/526

	British weights and measures.			or	Metric weights and measures.
	$\overbrace {\qquad \qquad \qquad \qquad }$				$\overbrace {\qquad \qquad \qquad \qquad }$
	Grains weight of substance	=	Grain measures of Vol. Sol.	or	Grams. wt. of Substance	=	C. C. of Vol. Sol.
Acid. Arseniosum	4.0	=	808	or	0.40	=	80.80
Acid.„ Sulphurosum	64.0	=	1000	or	6.40	=	100.00
Liquor Arsenicalis	442.0	=	875	or	44.20	=	87.50
Liquor„ Arsenici Hydrochloricus	442.0	=	875	or	44.20	=	87.50
Sodii Hyposulphis	24.8	=	1000	or	2.48	=	100.00

VOLUMETRIC SOLUTION OF NITRATE OF SILVER.

(Nitrate of Silver, ${\ce {AgNO3}}$ = 170.)

Take of

Nitrate of Silver	170 grains
Distilled Water	a sufficiency

Put the nitrate of silver into the 10,000 grain flask, and, having half filled the flask with water, allow the salt to dissolve; then dilute the solution with more water until it has the exact bulk of 10,000 grain-measures. The solution should be kept in an opaque stoppered bottle. 1,000 grain-measures of this solution contain 1/10th of a molecular weight in grains of nitrate of silver (or 17.0 grains).

Grammes and cubic centimetres may be employed instead of grains and grain-measures, but for convenience 1/10th of the numbers should be taken. 100 cubic centimetres contain 1/100th of a molecular weight in grammes of nitrate of silver (or 1.7 gramme).

It is used in testing the following substances:—

	British weights and measures.				Metric weights and measures.
	$\overbrace {\qquad \qquad \qquad \qquad }$				$\overbrace {\qquad \qquad \qquad \qquad }$
	Grains weight of substance	=	Grain measures of Vol. Sol.	or	Grams. wt. of Substance	=	C. C. of Vol. Sol.
Acid. Hydrocyan. Dil	270	=	1000	or	27.0	=	100.0
Ammonii Bromidum	5	=	508.5 to 514.5	or	0.5	=	50.85 to 51.45
Potassu Bromidum	10	=	838 to 850	or	1.0	=	83.8 to 85.0
Potassii Cyanidum	10	=	730	or	1.0	=	73.0
Potassii Iodidum	10	=	602	or	1.0	=	60.2
Sodii Bromidum	10	=	960	or	1.0	=	96.0
Sodii Iodidum	10	=	660	or	1.0	=	66.0