PRACTICAL PAPERS—BUTTER FACTORIES. 
237 
In testing, one of the cream-guages is filled to guage-mark 
10, with milk known to be pure, and drawn from several cows. 
This will be the standard for pure milk for that day. Another 
guage is filled to the same number (10), with milk from a 
can which you wish to test. To avoid any mistake, the first 
jar containing pure milk is marked with the letters P. M. on 
the side or bottom. The jars are set away side by side, a suffi¬ 
cient length of time for the cream to rise. Now note the quan¬ 
tity of cream in each. If a less quantity is found on the milk 
you are testing than on the other, it indicates dilution, or 
skimmed milk. Now remove the cream from each with a 
spoon, introduce the hydrometer (or l( lactometer,” as it is usu¬ 
ally called) into the jar marked P. M., and note on the scale- 
mark when it floats. Then remove it to the other jar, and note 
also when it floats. If it sinks lower than in the first jar, the 
evidence is considered almost positive of dilution with water. 
Replace the lactometer in jar marked P. M., from percent, glass 
filled with water exactly to nought or zero pour into P. M. jar 
until the lactometer sinks exactly to the same point as in the 
other jar. Now count a number on per cent, glass from zero 
down (each mark represents one-half of one per cent.) and you 
will have precisely the per centage of water with which the 
milk you are testing has been diluted. 
Although there may be considerable variation in the specific 
gravity of milk from different cows, it has been found that 
when the milk of several cows is mingled together, and when 
the milk of different herds of a neighborhood are compared, 
there is but little difference in the specific gravity of the sev¬ 
eral samples. 
These tests have been very effectual in bringing offenders to 
justice, and with the very strict law on the subject, very little 
trouble is now had on account of adulterated milk. 
ANNATTOINE. 
The butter factories prefer to give color to their butter by 
having the cows well fed, and by getting up the cream as 
