174 ANNUAL OF SCIENTIFIC DISCOYERT. 



as sensil)ly tho same, and that the experiment indicates that the 

 effoct is not due to lluid Irie-tion; at the same time they do not 

 su2')p()se that their experiments have yet conclusively decided the 

 origin of this heatin<^ eQ'eet, but they hope to elicit the opinions 

 oftliose interested iu the subject, wliich may serve to direct their 

 future research. 



INCREASE OF WEIGUT DURING COMBUSTION. 



The "Chemical News" gives a description of an interesting 

 experiment. A small horseslioe magnet is hung up at the beam 

 of a balance sufficiently sensitive to turn with centigrammes; 

 the poles of the magnet are immersed for a moment in the 

 limatura fori of the chemists' shops, and a beard of small parti- 

 cles of iron is caused to adhere to the poles ; by means of i)roper 

 weights placed on tlie scale-pan at tiie other end of the beam the 

 equihbrium is restored. Tiiis having been done, the fmely di- 

 vided iron is kindled, b}' approaching to it the llame of a Bunsen 

 gas-burner, and continues to burn. While burning, it will be 

 seen that the arm of the balance on which the magnet is sus- 

 pended considerald}' deviates from the horizontal position, thus 

 indicating an increase of weight on the side where the experi- 

 ment is going on. This exjieriment succeeds best with a magnet 

 ol moderate dimensions; the horseshoe magnet applied in this 

 instance weighed, without its armature, 210 grammes, and can 

 bear a load of 12.5 grammes of iron ; when this is altogether 

 converted in magnetic oxide, by combustion, the increase in 

 weight will be about 4.7 grammes. 



THE "blue cup OF THE CANDLE FLAME. 



E. W. Ililgard, on "Luminous Flames," in " Silliman's Jour- 

 nal,'' says : — 



" The part perfcn-med by the blue cup, namely, that of a self- 

 heating retort with Avails impervious to oxygen, in which dry 

 distillation is accomplished ; its theoretical import, as the coun- 

 terpart of the luminous portion, where the; same gases are burnt 

 with evolution of light; render the neglect with which it has been 

 treated doubly surprising. That it is totally distinct from the 

 outer v.eil is rapidly perceived when the eye is protected from 

 being dazzled by means of a screen of the shape and size of the 

 luminous hollow cone. The veil is then seen surrounding the 

 blue cup as well as the higlier portions of the llame, and is thus 

 proved to be nothing more than a zone of glowing gas; which, 

 of course, howx'ver, cannot be strictly delined from the luminous 

 envelope, the oxidation being a grachially progressive one, from 

 the highly luminous central portion to that browni.-h, semi-trans- 

 parent zone of transition, where the carbonic oxide, burning 

 simultaneously with hydrogen, fails to produce its characteristic 

 blue tint because of the excessive temperature existing there." 



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