400 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



each quart of milk, in form of a sirup, prepared by boiling it 

 for some time with half its weight of water, skimming, strain- 

 ing it through flannel, and cooling it to 167. The temperature 

 during evaporation is not allowed to rise above 189. When 

 sufficiently concentrated, as indicated by its dripping from 

 the stirrer in adherent masses, tin cans of from 1 to 2 pounds' 

 capacity, previously cleansed with soda-lye and heated well 

 for a few seconds, are filled completely with it, and the space 

 left by contraction, on cooling to from 66 to 73, is filled up 

 with hot, concentrated, purified sugar sirup, and the can is im- 

 mediately closed with a cap, and the joint covered with hot 

 flour-paste, and then with a strip of paper similarly coated. 

 Ten to eleven ounces of this preparation, with the addition 

 of a quart of water, are said to be equivalent in value to a 

 quart of pure milk. While analyses of several samples of con- 

 densed milk of the same specific gravity, by Professor Moser, 

 showed that one was much richer in the proper ingredients 

 of milk, and the other consequently in sugar, he does not con- 

 sider it advisable to carry the concentration too far, as may 

 be necessary to produce an 'article of the first kind, since the 

 milk is apt in such cases to acquire a tallowish taste, so fre- 

 quently noticed in condensed milk. 28 C, April, 1874, 299. 



EFFECT OF FEEDING OX THE COLOR OF COCOONS. 



The art of silk-culture is likely to be materially advanced 

 by the discovery of Taillis (if it be true) that when the worms 

 are fed on vine-leaves the cocoons are of a magnificent red, 

 and if lettuce be used, they become an emerald green. An- 

 other experimenter has obtained silk of a beautiful yellow, a 

 fine green, and then again violet, by feeding with lettuce or 

 white nettle. Taillis remarks, however, that the worms must 

 be fed on mulberry-leaves when young, following with other 

 leaves during the last twenty days of the larval stage of life. 

 16 A, October, 1873, 543. 



ARTIFICIAL HATCHING OF SILKWORMS' EGGS. 



A very curious discovery has been communicated by Susani, 

 an Italian scientist, to the French Society of Agriculturists, 

 to the effect that the hatching of silkworms' eggs may be ar- 

 tificially hastened by friction. The process consists, essen- 

 tially, in brushing the eggs vigorously, for ten or twelve min- 



