082 Transactions of the American Institute. 



repeats itself. From the 1st of January to June 8, he had observed 

 only six small groups; and out of one hundred and thirty-three 

 days of observation, there were one hundred without spots. In 

 the 3'car 1848, which is the middle of the 33.2 years' period, there 

 was a maximum of spots. If the thirty-three years' period should 

 be established by future observations, then a maximum of mete- 

 oric showers would always occur after three years of the usual 

 sun-spot periods. Whether this periodicity existed before, Mr. 

 Schwabe cannot decide; but he says there appears to have been a 

 minimum of sun spots in 1798.5, and a maximum in 1816.8. The 

 astronomers alluded to are now engaged in determining a curve of 

 spot-frequency during the last forty years, founded, not on the 

 number of the observed groups, but on the area of spotted sur- 

 faces, as observed by Hofrath Schwabe, by which the periodicity 

 will be represented with greater precision than before. 



The reading of this large number of scientific items, with the 

 remarks they elicited from Drs. Rich, Eichards, Bradley, Parmelee, 

 and others, occupied the whole evening, and at a late hour the 

 Association adjourned to next Thursday. 



September 26, 1867. 

 Prof. S. D. Tillman in the chair; J. Wtatt Reid, Esq., Secretary. 

 The Cnairman opened the proceedings by reading the following 

 notes on scientific progress: 



HERMETIC SEAL. 



A mixture of gelatine and glycerine, is liquid while hot, but on 

 cooling it becomes solid, retaining considerable elasticity and tough- 

 ness. The neck of a bottle dipped into this melted compound is 

 covered with an air-tight cap, which can be made as thick as desired 

 by repeating the operation. 



CEROLrNE. 



Professor Tozzetti, of Florence, has presented a note to the 

 French Academy of Sciences on the wax produced by the fig, 

 cochineal {coccm coricoe), which contains about half its weight of 

 cerolinc. He states that it may be procured in such large quan- 

 tities, as warrant its use in the industrial arts. 



