12 



turned by the handle D. B is the piston head with valve G 

 opening up and F opening downwards. H is the opening in 

 the cover and J a slide which slides in a groove on the lower 

 side of the cover. 



Suppose the pistonhead B is at the top ab, the can is full 

 of air. By screwing the pistonhead down to cd the air is ex- 

 pelled through the valve G. 



The milk is now poured in by the opening H so as to fill 

 the whole can and the opening H as well. This drives all (or 

 nearly all) the air out and the slide J is closed. 



The pistonhead is then screwed up to aft, letting the railk 

 through by P into the space c d e f where it is free from air.. 



When the milk is needed, a few turns on piston will press 

 some through G and it is poured out by H. The apparatus is 

 cleaned by unscrewing the cover at v and the inside of the can 

 as well as the pistonhead may be made of glass! 



Granted that this process will do all that it is claimed, 

 granted it will prevent the cream from rising, granted that 

 the anaerobic microbes cannot develop unless their aerobic 

 cousins have prepared the way for them and granted that the 

 latter cannot live without air, granted all this, my readers 

 will agree with me that the cost of such cans would preclude 

 their use. 



PRESERVING MILK UNDER PRESSURE. 



Experiments on this line w r ere made and reported by Prof. 

 B. H. Kite, in Bulletin 58, 1899, of West Virginia Experiment 

 Station. A 100-ton hydraulic press was used and in this the 

 milk enclosed in a lead tube abo.ut 1 inch in diameter and 5 

 inches long was submitted to a pressure in a solid steel cylin- 

 der of from 5 to 30 tons for one to three weeks. The best 

 results seemed to be obtained with a pressure of 

 from ten to fifteen tons for ten to fourteen days, and 

 the report says: "That the milk could be shipped a five or 

 ten days' journey, there can be little doubt, but the cylinders 

 capable of carrying such pressures would probably weigh 

 more than the milk." 



Experiments were also made using a pressure of from 5 

 to 20 tons and heating the milk to from 140 to 170 Fah. for 

 from five minutes to four hours, and it kept sweet for 19 days. 



Interesting as these experiments are, it seems to me there 



