362 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



acids. In drying fruits they should never be exposed to the direct rays of 

 the sun. In his opinion dried peaches were preferable to those preserved 

 in cans. 



Dr. Rowell stated that some time ag'o he purchased a bunch of. dried 

 peaches having the precise flavor of freshly picked fruit — they were pared, 

 quartered, and strung on threads so as not to touch each other. Heexhibi' 

 ted a self-sealing can Vvhich he had used for the past fourteen years — it 

 was made of earthernwarc and lined with glass. The cover was ground 

 to fit the top, and was tightened by turning it. 



Mr. AVatson exhibited a small jar of fruit which he said would keep fv.r 

 two years. He did not believe there was so great a change in the flavor of 

 canned fruit as had been previously stated. 



The Chairman said great improvement had been made in glass jars by 

 casting a thread in the glass. Such jars arc used for fruit. The pepper 

 cruet of an ordinary table caster, haviiig its cover held on b}' a glass thread, 

 cannot discharge its whole contents at once on the dinner plate. 



Mr. T. D. Stetson described minutely the manner of filling and scaling 

 these cans for preserving fruit. 



Dr. D. D. Parmelee gave an interesting account of experiments he had 

 tried in covering fruit with a thin coating of India rubber; decay was not 

 prevented by tin's process. If india rubber rings are used to keep cans 

 air-tight, they should be made with as little sulphur as possible in the pro- 

 cess of vulcanization. 



After selecting "The Manufacture of Gloves" as the subject for the next 

 discussion, the association adjourned to next Thursday evening. 



Amepjcan Institute Polytf.ciixic Association', ) 

 Oclubej- 6, 18 64. ) 



Chairman, Prof. S. D. Tillman; Secretary, B. Garve}-. 

 The Chairman presented the following interesting scientific memoranda: 



Revelations of the Spectrum. 



Father Secchi, of Rome, in a memoir to the Paris Academy of Science 

 gives the results of his observations on the atmosphere of the planet Jupiter 

 by the spectrum apparatus. The lines differ from those found in our own 

 atmosphere, and he infers that the two atmospheres are essentially different 

 in their chemical constitution 



Velocity of Electricity. 



M. Peliei, of Pisa, has measured with his new apparatus the velocity of 

 electricity, and finds it to be 2Gt),000 kilometers per second. A kilometer 

 is .0213 of an American mile. 



New Polarizing Prism. 



This contrivance, made under the direction of Prof. Dove, consists of an 

 isosceles right-angled pridin of calc-spar, one of whose sides is perpendicu- 

 lar and the other parallel to the optic axis of the crystal, and therefore the 



