142 ANNUAL OF SCIENTIFIC DISCOVERY. 



consequently, raised in this country, anions;' the many who use 

 the lime light, but weeks passsd a\va\' without anybody being 

 able to procure the zirconia cyliudirs in London. One night, 

 however, at a soiree at King's College, the zirconia light was 

 exhibited, burning with great steadiness and brilliancy, in the 

 presence of Professor W. Allen Miller, F.R.S., and many others, 

 but no accurate tests were made, and \)u\.\\ then and afterwards 

 the zirconia cylinders were as unprocurable in London as ever. 

 Three weeks since, however, one of the lirst zirconia lamps pro- 

 curable for examination, in this country, reached London, and 

 was sent by Mr. U. J. Fowler, the Parisian correspondfut of the 

 " Urilish Journal of Photography," to Mr. John Traill Taylor, 

 the editor of that journal, with the recpiest that he and Mr. W. 

 IL Harrison woulcl test its working qualities. The lamp was the 

 property of Messrs. Harvey, Reynolds, & Co., Leeds. Accord- 

 ingly, some experiments with the lamp were- tried at the work- 

 shops of Messrs. Darker Brothers, philosophical instrument manu- 

 facturers, at Lambeth. 



At present, the French company refuses to sell the zirconia 

 cylinders without their lamp be also purchased. According to 

 the "Engineer,'' this lamp, made for special use with the zirconia, 

 gives a vertical llame, and the piece of zirconia is held in it by a 

 little brass support. The piece of zirconia was (ixcessively 

 small, — about as big as a pea, — and here at once was a source 

 of great loss of light, because the llame was competent to raise 

 to whiteness several times the area presented to its action. On 

 this account alone, the total amount of light was very much less 

 than the same llame gave with a lime cylinder, so as to put com- 

 petition between the two out of the question, unless the zirc<mia 

 surface be very greatly increased in size. The experimentalists 

 then cut down a pTece of lime till it equalled the zirconia in size, 

 and the lime and zirconia were exposed in turn to the llame, the 

 result beinu: that the zirconia was found to emit a less white and 

 brilliant light than the lime under the same conditions, nor did 

 variations in distance from the nozzle of the jet alter this result. 

 Next, many variations in the pressure of the gases were tried, 

 but the result was not altered. Then, substituting an English 

 *' blow-through" jet for the blow-pipe sold by the French com- 

 pany, the same inferiority of the light from the zirconia was 

 perceptible, nor did variations of pressure aflfect the result. 

 Lastly, a good orthodox oxyhydrogen blow-pipe was tried, 

 wherein the two gases mix thoroughly some little distance behind 

 the nozzle, and again the results were the same. These conclu- 

 sions do not in any way affect the question of the permanency of 

 zirconia under the lierce heat of the oxyhydrogen llame ; but 

 such permanency, if purchased at the expense of inferior light, is 

 too diiarly bought, and will condemn the invention. Unless the 

 inventors are acquainted with some peculiarities of zir<;onia un- 

 known to those who arc versed in the use of the lime light, and 

 can, by an unknown method, bring out a light from the zirconia 

 equal to that given Ijy lime, the zirconia light, from an economical 

 jjoiut of view, is a failure. 



