118 
SELECTED ARTICLES. 
which appears to be the most rational, at the same time that 
it is most generally in use. 
Jirsenical solution of Fowler. Mineral liquor of Fowler, 
Liquor arsenicalis of the London Pharmacopoeia. 
The following is the London formula : — 
"Take, of sublimed white arsenic, reduced to a very fine 
powder, of subcarbonate of potassa, from tartar, each sixty- 
four grains, of compound spirit of lavender, four drachms, of 
distilled water one pint. Boil the white arsenic and the 
subcarbonate of potassa, in a glass vessel, until the arsenic shall 
be entirely dissolved; add the compound spirit of lavender to 
the liquid when cold, and finally add a sufficient quantity of 
distilled water to make up the pint." 
Let us investigate this. 1st. The sixty -four grains here 
directed are Troy grains, and they are equal to one drachm 
and -^-^ of a drachm French weight, since the English drachm 
sensibly of the same weight as our own, is divided into only 
sixty grains, instead of seventy-two, and five English grains 
are equal to six metrical grains. Consequently seventy-seven 
metrical grains are equal to sixty -four grains Troy. 2d. The 
English pint, used in the shops, is divided into sixteen fluid 
ounces, the value of which, when aqueous fluids are concerned, 
as in the present case, hardly differs from the medicinal 
ounce, each of which contains 480 grains Troy. The liquor 
thus prepared contains, then, four English grains to the ounce, 
or of arsenious acid. 3d. The compound spirit of 
lavender of the London Pharmacopoeia, is a true tincture of 
a deep red colour, prepared by infusing for fifteen days, in 
three English pints of spirit of lavender, and one of spirit of 
rosemary, half an ounce of cinnamon, half an ounce of nutmeg, 
and an ounce of red saunders. Hence it results that the 
liquor of Fowler almost possesses, in intensity, the smell, taste 
and colour of compound tincture of lavender, besides the 
taste peculiar to the arsenical salt which is formed. 
All foreign Pharmacopoeias, which contain the formula for 
Fowler's solution, give that of the London, filling up the pint 
(or octarius) to sixteen ounces in weight. These are, the 
