242 Some Eaperiments on skimmed Milk, 
only be determined by experiment. In order to satisfy myself 
on this point, I commenced a series of experiments on skimmed 
milk in February last, which have, with occasional interruptions, 
occupied me ever sinee.. I did not at first indulge any sanguine 
expectations as to the result of my investigation ; but after I 
had carefully made above a hundred experiments upon genuine 
skimmed milk procured from many of the principal dairy farms, 
embracing all the varieties of cattle, soil, and modes of feeding, 
common to this part of the country; and also examined many 
specimens of adulterated skimmed milk from the markets, I 
have at length ventured to construct a simple lactometer (on the 
well known principle of the hydrometer), the use of which, I have 
no doubt, will effectually prevent the frauds now practised in the 
sale of skimmed milk. 
Before I describe this instrument, it may be proper briefly to 
notice the cireumstances which led to its construction. My first 
experiments were directed to ascertain whether any uniformity 
exists in the density of different specimens of genuine skimmed 
milk ; accordingly I procured this article from many of the prin- 
cipal dairy farms, and from private houses in the neighbourhood. 
I also obtained new milk from the same sources, which I skimmed 
myself, after suffering the cream to remain on it about the usual 
time. The greater number of those specimens were of the spe- 
cifie gravity 1:037 and 1:0375. Some were higher, but the 
highest was 1-040, and the lowest 1036, the thermometer being 
at 50°. These experiments, confirmed by others which I after- 
wards made, led me to conclude that a considerable degree of 
uniformity prevails in the density of genuine skimmed milk; and 
this uniformity, I presume, would be still greater, if due allowance 
were made for accidental circumstances connected with the ex- 
periments, which, thongh not easy to appreciate, must, to a cer- 
tain extent, influence the specific gravity of milk ; as.for exam- 
ple, slight variations of temperature and of the balance employed ; 
to which must be added the unequal exposure to the atmosphere 
of the several specimens of milk examined. In reference to this 
1ast particular, it is proper to state that I found only one speci- 
men of milk of so high a specific gravity as 1-040; and in this in- 
stance the cream had been suffered to remain on the milk for 
above three days, and its specific gravity was not taken until 
some hours after it had been skimmed. These circumstances in- 
cline me to refer its superior density to CVEpOranions owing to pro- 
tracted exposure to the atmosphere. 
After I was satisfied concerning the degree of uniformity which 
exists in the density of genuine skimmed milk, my next object was 
to examine the skimmed milk brought to éfie markets in Cork, 
in order to ascertain the nature of the adulterations practised 
in 
© Caen 
