210 ANNUAL OF SCIENTIFIC DISCOVERT. 



the whole subject. Pure attar gives with iodine and with iodide 

 of potassium and starch the same reactions as when it is mixed 

 with geranium oil, and even those with pure geranium oil are 

 hardly dififerent. The proposed tests of NO5, NO4 and SO3 are 

 equally devoid of value. — Druggists' Circular. 



THE OXYGEN GAS-LIGHT. 



According to a letter of Dr. Doremus, of New York, as pub- 

 lished in the "Druggists' Circular" for 1868, pp. 252, 253, the 

 oxygen gas-light possesses the following advanta^^es : — 



i. It is more purely white than any of the lights ordinarily 

 used ; hence must be a blending of the various colors in quantity 

 and proportion more nearly approaching the sunbeam. All the 

 more delicate shades of whatever hue are seen almost as thouoh 

 illuminated by daylight. It is well known that this cannot be said 

 of coal gas, as ordinarily employed; for paintings, decorations, 

 colored dresses, ribbons, gloves, etc., present certain tints by nat- 

 ural light, and others by the usual artificial lights. 



2. It is many times more brilliant than the standard gas-light, 

 with the same consumption of coal gas. According to the French 

 reports, it excels by 16^ times that produced in the city of Paris. 

 I find it to exceed ours (that of the Manhattan Gas Company) 

 consumed in the English standard Argand burner, with 15 

 holes, and with glass chimney 7 inches in height, to the same, 

 and at times to a greater, extent. When this light is caused to 

 pass through the hot ascending current of gases from any ordi- 

 nary flame, the refraction of the light can be seen on a white 

 surface, literally causing these lights to produce their own 

 shadows. 



3. The light is steady and without flicker. Our "bat-wing" 

 and "fish-tail" burners yield wavy, tremulous flames, very trying 

 to the eyes, and especially annoying and injurious to those who 

 are obliged to employ artificial light for many consecutive hours. 

 Even the highly esteemed Argand cylinder of light loses charac- 

 ter when placed beside it. This must be so of necessity, for they 

 are flames, and therefore agitated by the constant currents of air 

 which they themselves excite and which may be produced by other 

 causes, while this light (the oxygen gas) emanates from a solid 

 pencil of compressed magnesia, fixed in a solid support, and ren- 

 dered incandescent by jets of carburetted hydrogen (or hydrogen) 

 burning with pure oxygen. 



4. Much less heat is thrown out by this light than from any of the 

 gas or petroleum flames, although it excels them all in brilliancy; 

 and the discrepancy is still greater if the comparison is made with 

 lights of equal illuminating power. The uncovered hand cannot 

 be held over the ordinar}?^ Argand burner, yet it may be placed 

 over this light with impunity, though it so far exceeds it in bright- 

 ness. The explanation of this apparent paradox is simple : Coal 

 gas, when mixed with air, as in the various forms of " Bunsen's 

 burners," so well known in chemical laboratories and used in 



