and an Account of a simple Lactometer. 248 
ia the sale of this article. Accordingly, 1 procured at different 
times, a great number of specimens from the milk markets; and 
on submitting them to a careful examination, I found that some © 
were genuine, and of course corresponded with good skimmed 
milk in every particular. Others were adulterated in different 
degrees, but the only foreign substance I could detect in the adul- 
terated specimens, was water. By adding a certain quantity of 
water to genuine skimmed milk, it became of the same density 
as the adulterated milks from the markets. By simple distillation, 
theadulterated milks furnished pure water, and became of the same 
density as genuine milk. In some cases, I found skimmed milk 
from the markets adulterated with,more than one-fifth of water ; 
i other instances, with about one-sixth, one-seventh, and one- 
eighth of water. The worst of the adulterated milks from the 
markets was of the specific gravity 1-026, the highest of the ge- 
nuine milks from the markets was 1-039, the thermometer being 
at 50°. 
It is, I believe, a common opinion that skimmed milk is adul- 
terated with other substances besides water; as for example, chalk, 
flour, starch, sugar, &c. which are said to be used for the pur- 
pose of concealing the water, by communicating as circumstances 
may require a certain degree of whiteness, thickness, or sweet- 
ness to milk, I have made a number of experiments to ascer- 
tain the correctness of this notion, and I am convinced the opi- 
nion is not well founded. Chalk is perfectly insoluble in skimmed 
milk, and soon subsides when mixed with it, on account of its 
superior density. Flour and starch inerease the density of skimmed 
milk, but this effect is only temporary; for, not being soluble, they 
gradually subside. The high price of sugar, were there no other 
consideration, precludes its use; for 1 have found by experiment 
that it would be too expensive even if it could be procured at 
the low rate of four-pence per pound. 
Those experiments on the density of genuine and adulterated 
skimmed milk (already noticed), which were made at the tempe- 
rature of 50°, I have since repeated at 60° Fahr. with similar 
results, making due allowance for the difference of temperature. 
I have examined the density of a great number of different speci- 
mens of genuine skimmed milk, but have not found any of a 
lower specific gravity than 1-035 at 60° of Fahrenheit. 
All my experiments concur to prove, that in the neighbour- 
hood of Cork, genuine skimmed milk obtained under nearly si- 
milar circumstances, varies comparatively but little in its den- 
sity; and that the only substance used to adulterate this article 
for the markets in Cork, is water. 
Skimmed milk aud water combine without undergoing any 
sensible alteration of volume, or condensation. Skimmed milk 
Hh 2 is 
