Intelligence and Miscellaneous Articles, 239 



uncharged electroscope, the electroscope becomes charged with 

 resinous electricitj', while no vitreous electricity is to be detected in 

 the tube. Tiiese facts are easily explained. The tube does not 

 retain the vitreous electricity, because its internal conductibility 

 being very great, this electricity can escape into the earth ; but the 

 electroscope remains charged with resinous electricity, because the 

 small external conductibility of the tube only suffers it to escape 

 very gradually. 



If, instead of holding the tube in the naked hand, you fix it to the 

 extremity of an insulating handle, you can easily electrify it by 

 rubbing it with a woollen cloth ; if you then place it in contact 

 with an uncharged electroscope, the latter becomes gradually charged, 

 and the charge continues when the tube is removed. The charge is 

 effected slowly, on account of the resistance encountered by the 

 electric fluid in passing from the tube to the electroscope ; but it 

 takes place without any change in the point of contact, on account 

 of the facility with which the electricity passes from one end of the 

 tube to the other. 



If, on the contrary, a stick of gum-lac be electrified, and an elec- 

 troscope be simply touched with it, a permanent charge cannot be 

 obtained unless the tension of the electricity be very great ; since 

 the internal conductibility being exceedingly small, the electroscope 

 only receives the electricity of the parts of the stick with which it 

 is in immediate contact. If, however, the electrified stick be drawn 

 along the support of the electroscope, a permanent charge is readily 

 obtained, since, the external conductibility being great, the points 

 successively touched i)art at once with the electricity they possess. 

 — Comptes Rendus, May 23, 1859. 



ON ALCOHOLIC FERMENTATION. BY L. PASTEUR. 



When the accurate analyses of Gay-Lussac and Thenard and those 

 of De Saussure had definitely established tlie composition of sugar 

 and alctihol, it became easy to show theoretically that by mixing 

 alcohol and carbonic acid, the c()inpo>ition of sugar niiglit be repro- 

 duced. This was indicated by Ga)-Lnssac in a letter addressed by 

 him to M. Clement in 1815, which concludes thus: — " If we suppose 

 now that the products furnished by the ferment may be disregarded 

 in relation to the alci)hol and carbonic acid which are the only 

 sensible results of fermentation, we shall find that of 100 parts of 

 sugar, Sl'.S't are converted into alcohol, and 4'8*66 into carbonic 

 acid during fprmentation." This deduction of Gay-Lussac co- 

 incided with the views promulgated twenty-five years before by 

 Lavoisier upon alcoholic fermentation, and it removed all the doubts 

 which sooner or later must have been raised by the inaccurate expe- 

 riments oi that illustrious chemist. 



It was admitted, however, that experiment could not in all points 

 confirm Gay-Lussuc's theories, for Lavoisier had rightly indicated 

 tlial a small portion uf sugar was transformed into an organic acid, 



