982 



PRACTICE OF AGRICULTURE. 



Part III. 



to allow the whey to escape while the cheese is pressing : the size of vats must depend 

 on that of the cheese and the number required, as of most of the other implements 

 on the extent of the dairy. The cheese-press 

 {Jig' 661.), is a power generally obtained by 

 a screw, though sometimes by a dead weight, and 

 is used for forcing the whey from the curd while 

 in the vat. The cheese-tongs is a wooden 

 frame, occasionally placed on the cheese- tub, 

 when the vat is set on it in order to drain the 

 whey from the curd. To these implements some 

 662 add a lactometer, one kind of which {Jig. 

 662. ), is a glass tube a foot long, with a 

 funnel at top. The upper two inches 

 of the tube are marked in small divi- 

 sions, and when t' e instrument is filled 

 to the height of one foot with milk, the 

 depth of cream it yields is noted by the 

 gradations on the upper part. Another 

 lactometer " for ascertaining the rich- 

 ness of milk from its specific gravity, 

 by its degree of warmth taken by a 

 thermometer, oa comparing its specific 

 gravity with its warmth," was invented by Dicas, 

 of Liverpool, but never came into use. Ano- 

 ther invention for the same purpose was made by 

 Mrs. Lovi, of Edinburgh, in 1816. It consists 

 of aereometric beads, by which the specific gravity 

 of the milk is tried first when new-milked, and 

 next when the cream is removed. "When milk is tried as soon as it cools, say to 60, 

 and again, after it has been thoroughly skimmed, it will be found that the skimmed milk 

 is of considerably greater gravity ; and as this increase depends upon the separation of 

 the lighter cream, the amount of the increase, or the difference between the specific gra- 

 vity of the fresh and skimmed milk, will bear proportion to, and may be employed as a 

 TTCieasure of, the relative quantities of the oily matter or butter contained in different 

 milks. The specific gravity of skimmed milk depends both on the quantity of the sac- 

 charo-saline matters, and of the curd. To estimate the relative quantities of curd, and 

 by that determine the value of milk for the purpose of yielding cheese, it is only re- 

 quired to curdle the skim-milk, and ascertain the specific gravity of the whey, The 

 whey will, of course, be found of lower specific gravity than the skimmed milk, and the 

 number of degrees of difference affords a measure of the relative quantities of the curd. 

 According to this hypothesis, the aereometric beads may be employed to ascertain the 

 qualities of milk, relatively both to the manufacture of butter and cheese. {Trans, o/" 

 the High. Soc. sect. v. part i.) 



6311. In milk coolers and churns there is considerable variation of form. Milk cool- 

 ers are generally made of earthern ware or wood ; but of late years they have been formed 

 of lead, marble, slate, and cast iron. Their general form is round, and diameter from 

 one to two feet ; but in extensive dairies they are often made several feet or yards in length, 

 and from two to three feet wide, with holes at one or more corners to admit the escape of 

 the milk after the cream is removed. The safest dish is wood, though it requires most 

 labor to keep it sweet ; next is earthen ware or china, though on the leaden glaze of the 

 former, the acid of the milk is apt to operate. Leaden dishes or troughs, though very 

 general in Cheshire, are the most dangerous ; and the objection to slate coolers is the 

 joinings of the plates, which are always unsightly, imperfect, and liable to be operated on 

 by the lactic acid. The annealed and tinned cast iron dishes of Baird's invention (in 

 1806), and which are now becoming universal in Scotland, are perhaps the best for such 

 as do not chose to go to the expense of China dishes. They are durable from the nature 

 of the material, not liable to be broken by falls from being annealed, easily kept clean from 

 being turned smooth, and also very economical, and said to throw up more cream from a 

 given quantity of milk than any other. 



6312. With respect to churns, besides the common plunge and barrel churns, there 

 are various improved sorts. One of the best for using on a small scale is the patent box 

 churn {Jig. 663.) ; and on a large scale the plunge churn, worked by levers put in motion 

 either by a man or horse. The Derbyshire churn {Jig. 664.)^ which works on the prin- 

 ciple of the barrel churn, is an excellent implement on a large scale. The bottom is a 

 segment of a circle, and the advantage of the plan is, that when the butter is made, 

 the lid () being removed the beaters {b) may be taken out at pleasure by with- 



