686 CATTLE AND DAIRY FARMING. 



balk than a similar volume of milk weighing 1,029 pounds to 1,033 pounds, accord- 

 ing to its quality; and, bearing this in mind, Quevenne taking off the ten, used the 

 other two figures upon his lactometer. His scale commences at 14, which is at the top, 

 and descends to 42 at the bottom. It is apparent that 14 (otherwise 1014) is far too low 

 to be pure, but the margin is a wide one, while 42 (1042) is just as much the other way. 



When the instrument is placed in the milk (which should be done very gently, in order 

 that it may not sink, and cause milk to adhere to a point above that at which it floats, 

 or it will not be true), the figure which is level with the surface will show the true state 

 of the case. Thus, in Quevenne's, if it rests between 29 and 33 it is pure; if between 

 27 and 29, ^o water has been added; between 24 and 26, -^e; if between 21 and 23, j%; 

 and so on. A sketch of this instrument is shown. 



With English lactometers the scale commences at the bottom at 10, goes up to 0, and 

 then up to 100, at the top. Pure milk marks 0, pure water 100; thus every figure be- 

 tween shows the actual adulteration, the ten Spaces below indicating when milk has 

 been skimmed. These lactometers are usually employed in milk heated to 60° Fahr., 

 while the Quevenne is used at 59° Fahr. (15° centigrade and 12° Eeamur). 



An advantage of Quevenne's scale is that it tests skimmed milk as well as whole 

 milk, the same figures being made to apply by being bracketed; thus 33 to 36 indicate 

 purity, and skim milk being heavier than new milk, the lightest portion, cream, being 

 skimmed from it, while the addition of water is shown between 32 and 17. There is no 

 doubt that Quevenne's instrument acts well when used for mixed milk; but it often 

 varies considerably with the pure milk of individual cows. 



In using the lactometer it is best to have a deep and narrow glass vessel, similar to a 

 creamometer, in which the milk is poured at the right temperature. When the instru- 

 ment is placed in the milk, it must be held by the stem until it floats at the right mark; 

 that it be not made too heavy, as mentioned above. If it sinks below the pure-milk 

 mark the percentage of watering may be suspected. Thus, supposing the lactometer to 

 be an English one, measuring to 100, if one-half the liquid be water and the other half 

 milk, it will sink to 50; if 20 per cent, of water is added, it will sink to 20, and so on. 



It must be remembered that the lactometer can not be expected to do more than it 

 professes; it denotes the gravity of milk, and if that gravity is anywhere near the aver- 

 age, all well and good; but, as the milk of different cows varies in gravity, so does the 

 instrument cease to be a specific guide when applied to these distinct samples. If in 

 testing a sample it is found lighter than the average, there is reasonable suspicion that 

 it has been watered; if, on the contrary, it is found heavier,Hhere is ground for believing 

 that it has been skimmed. 



The English lactometer shows this on the scale 10 to 0. It has been shown that inasmuch 

 as cream, like water, is lighter than milk, a sample heavy in cream would appear to be 

 adulterated just as though it had been watered; while, on the other hand, if saltor sugar 

 were dissolved in the milk, they, being heavier, would cause it to show that, to all ap- 

 pearance, the milk had been skimmed. Thus it is always well to use the crearaome- 

 tor and lactometer in conjunction with each other, so that when both point to watering 

 or skimming there is little doubt of the fact. Again, it is well to use the creamometer 

 even when the lactometer is satisfactory, for it can be cheated. As has been shown, if 

 water is added to milk it is made lighter, And that if skimmed it becomes heavier from 

 the loss of its lightest constituent; it is therefore possible to first skim it and then briog 

 it back to its normal gravity by the addition of water. Although the lactometer would 

 not detect this, the creamometer would. 



It was found by Chevalier, by experiment, that the value of the glass creamometer is 

 much regulated by its diameter, in accordance with its height. In using it the milk is 

 poured in until it reaches the top line, 0°, and left for twenty-four hours in a room at 

 about 60°, by which time it will have formed a cream of 7° to 25°, according to its rich- 

 ness. This instrument is valuable, as shown above, for use in conjunction with the lac- 

 tometer, and also for testing the cream yield of individual cows. By it special feeding 

 may be tested, and thus considerable expense saved. It must not be inferred that the 

 quality of the cream is shown by the creamometer, for cows giving the same quantity 

 often make less butter than others. At the same time the cream test by this plan is a 

 very valuable one. 



The thermometer is a most necessary instrument in the dairy, as without it the work 

 is accomplished by guess ; and in spite of those who prefer to trust to their innate knowl- 

 edge of temperature, there is no doubt that the result affects the quality of both butter 

 and cheese very materially. 



A lactoscope was recently invented by Professor Feser, of Munich, which is based upon 

 the measurement of the degree of transparency of milk, which depends chiefly on the (at 

 it contains. The instrument consists of a graduated tube, marked with a double scale, 

 and a pipette, which is filled with the milk to be tested. This is then poured into the 

 large tube, when water is added until the black lines are visible. The oercentasie of fat 



