Miscellaneous Implemenis Exhibited at Warwich. 643 
thirds of the surface) evidently interfered very considerably 
with the effect of the side forks, although the land was not 
soft or Avet. This may probably be remedied to some extent 
by adjusting the centre roller to carry more of the weight. 
The effect of pressure of this kind could only really be estimated 
by seeing the succeeding crop. Much would depend upon the 
description of the soil and the state of the land when the work 
was done. On some lands the compression would not reach so 
deeply as on others, and would not have so injurious an effect. 
The following particulars as to work per day were given 
to me. The machine breaks up about five acres per day of 
ten hours during the summer — allowing for stoppages ; it is 
regulated to travel at an uniform speed of about one mile 
per hour, and the depth to which the land is dug does not 
materially affect the quantity. It consumes from 11 to 15 cwt. 
of coal per day of ten hours, according to quality. The charge 
per day when hired out is from 10.?. to 15s. per acre, accord- 
ing to circumstances, but the depth does not affect the 
charge. 
VIII. Other Miscellaneous Implements. 
Article G02. Messrs. R. A. Lister & Co., Dnrsley, exhibited a 
Tester, the “ Positive,” for milk. This is described as a machine 
for ascertaining the actual butter-fat in new milk, skim milk, or 
whey. It is a method introduced by Dr. Babcock, of the United 
States, and is known as the Babcock method. The construction 
of the machine, which is turned by hand, is veiy simple. A 
circular pan, about four inches deep, revolves on a spindle j 
there are four cups or pockets in the pan, in which to place 
the test glasses, the number of pockets varying according to the 
size of the machine. An even number of test glasses should 
be put into the pan, and placed opposite to each other, to 
maintain the equilibrium. A quantity, of milk, measured in a 
pipette, is put into a test glass which has a bulb with a gradu- 
ated neck or stem. A measured amount of sulphuric acid is 
then added to it ; the milk and acid are next shaken up and 
mixed ; the mixture turns quite black, and the glass becomes 
very hot ; it is at once placed in one of the pockets, and the 
pan is rotated for seven or eight minutes at from 400 to 500 
revolutions a minute. The test glass is next filled up to a 
mark on the stem with hot water, hot water is also put into 
the pan to the depth of about two inches, and it is again rotated 
for one or two minutes ; the glasses are again taken out and 
filled up with hot water to a certain mark on the gauged stem. 
If necessary, more hot water is put into the pan, and the 
