388 Intelligence and Miscellaneous Articles. 



means by which they may be obtained, have convinced me that they 

 will become useful to the chemist and manufacturer ; I have there- 

 fore decided upon submitting to the Academy the details of the 

 operation, which, I trust, will not be found unworthy of attention. 



The apparatus which I employ is a simj)le furnace 30 centimetres 

 high and 18 centimetres diameter, supported upon a plate of cast- 

 iron pierced with holes arranged in a circle 5 centimetres from the 

 centre. This is placed in communication with the bellows of a 

 portable forge. 



The best kind of crucibles melt down at the temperature in ques- 

 tion to a perfectly liquid glass, and for a substitute I was obliged to 

 have recourse to pieces of well- burnt lime, which may easily be 

 brought into the shape of thick crucibles. Their covers are likewise 

 made of lime. M. Berthier observed that hydraulic limes were rea- 

 dily fused at a high temperature, and I have found that perfectly 

 pure lime very frequently agglutinated. It is therefore indispensable 

 to employ a somewhat porous lime, slightly siliceous, which will 

 only become compact at the most elevated temperatures. 



With regard to the combustible, it must be very porous and in a 

 state of very fine division ; and I should add that I succeeded only 

 when I made use of the residue of the imperfect combustion of coal, 

 the clinkers mixed with cinders which fall from the grate of the 

 heating apparatus and still at the Ecole Normale, passed through a 

 wire sieve. With coal of the best quality, in very small particles, 

 the effects are much more feeble and do not differ from those which 

 have already been obtained. 



This extremely elevated temperature is developed with such rapi- 

 dity that in a few minutes it reaches its maximum. But it does not 

 extend beyond a small distance upwards, carbonic oxide being formed 

 higher up with a considerable reduction of temperature, and the pro- 

 duction of a very long and feebly heated flame. M. Ebelmen has 

 perfectly explained this phsenomenon, the cause of which is now 

 generally known. — Comptes Rendus, November 1852. 



NOTE ON THE REPRODUCTION OF ENGRAVINGS AND DRAWINGS 

 BY MEANS OF THE VAPOUR OF IODINE. BY M. NIEPCE DE 

 SAINT VICTOR. 



In 1847 the author published a memoir on the action of different 

 vapours, and amongst others of that of iodine. He stated that the 

 vapour of iodine attached itself to the black portions of an engraving 

 to the exclusion of the whites, so that the picture could be repro- 

 duced on paper sized with starch, or on glass coated with this 

 substance ; in this manner designs were produced, but they could 

 not be rendered very permanent. 



The author now proposes to render them unalterable by the fol- 

 lowing processes : — If a design obtained on starched paper or glass 



melted in lime, a crucible cover upon which were numerous globules of 

 platinum which had been volatilized, and a specimen of piu-e siuca melted 

 ID graphite. 



