176 ANNUAL OF SCIENTIFIC DISCOVERY. 



Instead of throwing: tho sheet of air perpendieularly to the 

 flame, M. L. Dulour tliuiks it better to throw it partly on one 

 side, on sueh a phme as to make a slii^ht anfi;le with tlie axis of 

 the conical flame, or with the plane of the Ian-shaped flame. A 

 lateral section is then produced by the influence of the current, 

 which draws the flame, and inelin<\s it af]:;ainst the sheet of air, by 

 wliicli it is cut. By placinLT the sheet of air on a more or less 

 inclined plane, and api)roachin«^ or removin<^ it from the base of 

 the flame, the section is easily made at j^oints more or less dis- 

 tant from that base. 



The metliod described above may, of course, be applied to any 

 kind of flame. M. L. Dufour suggests that it miglit be of ser- 

 vice in the chemical analysis of flames. AVhen a flame is cut by 

 a sheet of w^ater, the water draws oft' the gases ijy which it is 

 composed. If the section be made with a sheet of air, it will be 

 easy, by i)lacing suction pipes throughout the length, and ending 

 at fixed points in the interior of the cone, to collect the gases 

 whose composition is desired to be ascertained. — Chemical News. 



monckhoven's new artificial light. 



Dr. Desire van Monckhovcn recently demonstrated satisfac- 

 toril3'its imj)ortance before a meeting of the Vienna Photographic 

 Society, and delivered a lecture upon its mode of application. 



One of the most intense lights to be obtained l3y oxidizing 

 metals or metallic compounds at a high temperature, is that 

 derived from chloride of titanium, or chloro-chromic acid, when 

 exposed to the action of an oxy-hydrogen flame ; the light thus 

 produced is of high actinic power, and cajialjle of blackening 

 chloride of silver paper to an appreciable degree in 30 seconds, 

 the formation of titanic acid or chromic acid being brought about 

 at a very high temjierature. It is this descrii)tion of light that 

 has been chosen by Dr. M. 



Several kinds of oxy-hydrogen lights have been devised from 

 time to time; the Drummond light, in which the flame acts 

 against a cylinder of unslaked lime, but which requires the con- 

 stant presence of carbonate of lime, and the surface of the cyl- 

 inder to be continually changing; the Tessie du Motay light, in 

 which the lime cylinder is replaced by means of a compressed 

 magnesia or zirconia cylinder ; and the Carlcvaris light, consist- 

 ing of small parallel pipes of hard charcoal moistened with 

 chloride of magnesium. Of all these lights, that of Drummond 

 is the best, and by substituting for the lime cylinder another com- 

 posed of titanic acid, magnesia, and carbonate of magnesia, a 

 suitable illuminating power is obtained. A cylinder of this 

 description, measuring 3 centimetres (one inch) broad, and 9 

 long (3 inches), lasts for 3 hours, and may be produced for the 

 sum of threepence. Instead of hydrogen, ordinary coal gas is 

 employed; and for the supply of oxygen, i\I. Deville's method 

 of obtaining it by heating a mixture of calcined peroxide of 

 manganese and chlorate of potash is employed. 



