416 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



They use a lamp made of a pint bottle, having two openings 

 through the cork, and filled with fragments of some porous 

 substance, as sj^onge, coke, or pumice, for the purpose of im- 

 bibing the sulphide of carbon. A tube, reaching within one 

 fourth of an inch of the bottom, passes through one opening 

 in the cork, and a larger one through the other opening. 

 This is about eight inches long, and may be of glass or metal, 

 and is closely packed around with iron-scale. The object, 

 like that of the gauze in the safety-lamp, is to prevent the 

 return of the flame into the bottle, and its consequent explo- 

 sion. The nitric oxide gas is passed into the bottle through 

 the first-mentioned tube, and the gaseous mixture is conduct- 

 ed by a rubber tube to a kind of Bunsen burner, the air-holes 

 of which are closed, and which is furnished with a small 

 conical valve to regulate the flow of gas. This burner is also 

 filled with iron-scale. The nitric oxide gas is produced in 

 the cold by Sainte-Claire Deville's method, by the action of 

 a mixture of nitric and sulphuric acids upon metallic iron. 

 With an apparatus of quite moderate dimensions a dazzling 

 flame, not less than ten inches in height, can be obtained, 

 abundantly sufficient for the purposes of j^hotographic work. 

 It has been estimated that the photographic power of the 

 lamp is superior to that of magnesium, is twice as great as 

 that of the oxyhydrogen light, and three times as great as 

 that of the electric light. Furthermore, the flame is absolute- 

 ly steady, and there is no danger of its sudden extinction, as 

 with magnesium; and the eye can sustain its brilliance with- 

 out being aflected. Its cost is much less than that of either 

 of the other lights. 1 j9, December, 1874, 381. 



GLYCERINE FOR ILLUMIXATION AND HEATING. 



Godefi*roy, of Vienna, found that chemically pure glycerine 

 (sp. gr. 1.2609), when heated to 302, burned quietly with a 

 blue, non-luminous flame, without the least odor and without 

 leaving any residue, and also that glycerine of low specific 

 gravity, if not too dilute, may be burned by means of a wick 

 or cotton immersed in it, in an open porcelain capsule. Scher- 

 ing has recently communicated the fact that it can be burned 

 in any lamp in which the flame is immediately above the 

 level of the liquid (such as the Berzelius lamp), its thick con- 

 sistency preventing its giving a constant flame with a higher 



