377 



(12) The wider tbo fnrrow up to the standard cutting width of the plow, the less 

 the force required to tarn a square inch of soil. After passing this width the draft 

 on a clover sward still very slightly continued to decrease. On old ground it did 

 not decrease heyond this point. 



(13) Draft decreased with deptli and probahly will as long as the, soil retains the 

 essential jdiysical conditions of the snrlace. 



Vermont Station, Bulletin No. 21, September, 1890 (pp. 26). 



A NEW MILK TEST. — This test depends upon dissolving the curd 

 (casein, albumen, etc.) of 15 cubic centimeters of milk in a mixture 

 of hydrochloric acid and amyl alcohol with concentrated sulphuric 

 acid, and then wliirling the bottles containing the liquid in an im- 

 proved centrifuge (a modification of Beimling's patent) from one half 

 to one minute, when the clear fat will be found collected in the 

 narrow neck of the test bottle. No heat or hot water is used in the 

 separation. The reading of the fat column by the graduation on the 

 neck of the bottle indicates the percentage of fat in the milk directly, 

 without calculation. 



"The centrifugal machine consists of a central axis, to which are at- 

 tached as many pockets as are desired. Machines are usually made to 

 contain 3, 6, 12, or 24 pockets. The pockets are attached to the shaft 

 by a hinge-joint that enables them to hang perpendicularly when the ma- 

 chine is at rest, but allows them to straighten out horizontally when 

 they are revolved. By this means there is no danger of loss from spill- 

 ing on starting or stopping, even when the bottles are nearly full. The 

 pockets are water-tight, so that should a bottle break its contents could 

 not do any damage. * * * The conditions of a successful test are : 

 an acid liquid, colored more or less purple; a clear, cloudless column of 

 fat; and either no undissolved casein whatever, or but a thin layer 

 (one thirtieth of an inch). If much casein remains, or the fat be cloudy, 

 the result will be likely to be untrustworthy, and the test should be 

 repeated. * * * In a set of twenty-four samples, in which the work 

 with the new machine was done by one who had never used the machine 

 but once before, 75 per cent of the results agreed with the Adams 

 gravimetric method within a tenth of 1 per cent and in no result was 

 there as much as three tenths difference." 



Skim and buttermilk containing less than 1 per cent of fat can not 

 be accurately tested by this method. In testing cream 10 cubic centi- 

 meters djhited with water may be used in the ordinary testing bottle, 

 the reading being corrected by the factor 1.45. The time required for 

 a single test is not more than five minutes, or twenty-five determina- 

 tions can be made in an hour. The cost of chemicals does not exceed 

 one fifth of a cent per test. The centrifugal machine, which is patented, 

 costs from $20 to $50, according to size, one carrying six tubes costing, 

 with test bottles, $25. 



