THE DAIRY.

New Zealand Mail, Issue 936, 7 February 1890, Page 18

THE DAIRY.

THE LACTOMETER. The report of the case has been going the rounds of the papers in which the use of the lactometer in testing milk led to a very grave error. This instrument is by far the handiest of all the different kinds of apparatus used for this purpose, but it is a great pity that, und-u- certain circumstances, it is misleading, aud we propose in this article to point out wherein such mistakes mast be avoided. The lactometer is simply the hydrometer with the stem graduated to suit the density of milk, and depends for its action on the difference of the specific gravity ot different fluid*. The standard or starting point is taken as the specific gravity of water as, 1,000 at a temperature of 60 deg bahr, and it is found that if the stem of the mstrumont is graduated from this point and put in milk it will sink to 1030 or 1032. In other words, milk is about three per cent heavier than water, gallon for gallon, though there is a slight difference between different samples. Now, if milk were diluted with about its own bulk of water, so as to make it ‘ half aud half,’ it follows that the lacto meter would sink to about midway between the 1000 aud 1030, or say 1015 ; and if any other proportion of water were it would sink proportionately, so that it is possible to tell how much water has been added to ordinary samples of milk with approximate correctness. Bub we have not always got to deal with ordinary samples, and when unusual ones turn up the lactometer is at fault. Milk contains a large quantity of fatty material (butter-fats), and. like all other fats, it is lighter than water, this being, in fact, one reason why cream floats on the top. The specific gravity of cream is slightly more than that of water, while the butter itself is only about 912. The cream in the milk thus tends to reduce its specific gravity, so that while ordinary milk, with 3| per cent of fat, will show, say, 1030 on the scale, a sample with 5 per cent of fat will show only, sa y> 1028, or, in other words, the reading of the lactometer for very rich milk will be the same as for ordinary milk which has been watered. It was a case of this kind to which we rsfer above, a milk-dealer refusing to take milk from a farmer because the lactometer reading was low, while analysis showed that this lowness was due to the milk being very rich in fat. . But there is another way in which the lactometer is misleading. While excess of fat lowers the specific gravity, removal of the fat will raise it. In other words, if milk has been skimmed, it will perhaps show as high a reading as 1034 or oven 1036, and if water be added to this skim-milk it will again reduce it, so that milk both creamed and watered will show the same figure as a good ordinary sample. From all thi3 it will be seen that the lactometer is a very unreliable instrument, quire as iikoly to mislead as to put right. There is another simple piece ot apparatus, however, which if used along wish it will act as a check, and the two together give very good results. This is the creamometer, which shows the percentage of cream and which indeed is usually sold along with the other as forming a convenient vessel tor holding the milk to be tested . If the degrees of cream are known along with the specine gravity, then tho result will be approximate y correct. Thus a lower specific gravity tnan 1030 will be correct if the cream is abnormally high, while if the cream is low also it indicates watering. After all, however, while a rough and ready test such as this is very useful, it would not do when accurate work is required, and is not fco bo depende on too much. The ordinary analysis by a chemist, though more tedious, must be resorted to if tiuire are consequences of great importance attached to the examination, English Paper. DAIRYING- IN NORMANDY, PRANCE. The freshness of the pastures in Calvados in July surpasses that of the valleys of the Mohawk, the Delaware or the <?usqushanna. The town of Isigny is a central market for butter. The cows that yield the milk from which the highest-priced butter of the world is made, are nearly pure-bred Cotentin. These cows of Normandy are large, grand, looking animals, the best giving, when fresh, twenty quarts of milk daily, and through a long term of annual lactation. It requires about twelve quarts of milk to a pound of butter on grass alone. There is a substantial, business-like !o k to a herd of these cows. Not too fine, nor yet too coarse. Ido not know that there has ever been a single importation of the Cotentin or Norman breed of cattle into the United States. France exports nearly 1,000,000 pounds of butter annually. Isigny butter at wholesale sells at auction in Paris for seventy-five cents par pound in winter. Nearly one-half of the butter.imported into England comes from France. One house in London makes in commission* on butter imported from France about SO.OOOdols annually, and that business is managed by a woman. As a cheese-producing cow, the Cotentin fairly compares with the excellence in butter. The Comernberfc cheese, made from her milk in the Paris Exposition of 1874, took the champion gold medal against three such competitors as the renowned Brie, Gruyore and Conloimnier-’. Tho report of the judges contains the following statement : ‘ It surpasses in delicacy everything that the ingenuity o' the- cheese manufacturer has been able to invent to flatter the most fastidious palate.’ But subsequently, fickle fashion’s fastidious taste selected the delicious and piquant Roquefort in 1875; and it again

changed in 1876 to the Gruyere. With a rivalry of seventy varieties of chesse, every gustatory fancy might be fully satisfied.. Patient and exact manipulation, cleanliness to severity in every step of butter-making and cheese-manufacture, are the elements that enter into the products, next in importance to the cream and milk. It is because of these national traits that the handicraft of the French secure such excellent products from whatever materials wrought. Painstaking is too seldom a factor in our manufactures. Rapid manufacture and sleight-of-hand mar too many of our domestic goods. In Isigny, the hand never touches the butter, which is pressed In clean, sweet cottou cloths until the butter-milk is removed. The same care i 3 shown in every step of handling dairy products. When a drop of milk, cream or any substance falls to the floor, it is either carefully wiped up or removed by flowing water. Like our teatasters, butter experts have so keenly cultivated the sense of taste that they can accurately replace samples of .butter previously examined without seeing whence they were taken, though a dozen samples have been arranged to verify the previous judgment,—H. S. Ericus, Isigny, France.