81 
THE NEW ZIRCONIA-LIGHT. 
Three or four months ago the news spread in England, through the medium of the 
scientific newspapers, that a discovery had been made in France which would have the 
effect of abolishing the lime-light by substituting zirconia for the lime cylinder. The 
advantages were stated to be that zirconia is not eaten away by the oxyhydrogen flame, 
and that when not in use it does not absorb moisture and crumble to pieces like lime ; 
also, that in consequence of this stability the ordinary clockwork of oxyhydrogen lamps 
to turn the lime cylinder would be unnecessary with zirconia. It was further said that 
the zirconia gave more light than lime under the same oxyhydrogen flame. 
Considerable interest in the new invention was consequently raised in this country 
among the many who use the lime-light, but weeks passed away without anybody being 
able to procure the zirconia cylinders in London. One night, however, at a soiree at 
King’s College, the zirconia-light was exhibited burning with great steadiness and bril¬ 
liancy in the presence of Professor W. Allen Miller, F.R.S., and many others, but no ac¬ 
curate tests were made, and both then and afterwards the zirconia cylinders were as un¬ 
procurable in London as ever. 
Quite recently one of the first zirconia lamps procurable for examination in this coun¬ 
try reached London, and was sent by Mr. R. J. Fowler, the Parisian correspondent of the 
‘British Journal of Photography,’ to Mr. John Traill Taylor, the editor of that journal, 
with the request that he and Mr. W. H. Harrison would test its working qualities. The 
lamp was the property of Messrs. Harvey, Reynolds, and Co., Leeds. Accordingly, last 
Wednesday some experiments with the lamp were tried at the workshops of Messrs. 
Darker Brothers, philosophical instrument manufacturers, at Lambeth. 
At present, we are informed, the French company refuses to sell the zirconia cylinders 
without their lamp be also purchased. This lamp, made for special use with the zir¬ 
conia, gives a vertical flame, and the piece of zirconia is held in it by a little brass sup¬ 
port. The piece of zirconia was excessively small—about as big as a pea—and here at 
once was a source of great loss of light, because the flame 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 flame gave with a lime cylinder, so 
as to put competition between the two out of the question, unless the zirconia surface 
be very greatly increased in size. 
The experimentalists then cut down a piece of lime till it equalled the zirconia in size, 
and the lime and zirconia were exposed in turn to the flame, the result being 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 blowpipe sold by 
the French company, the same inferiority of the light from the zirconia was perceptible, 
nor did variations of pressure affect the result. Lastly, a good orthodox oxyhydrogen 
blowpipe was tried, wherein the two gases mix thoroughly some little distance behind 
the nozzle, and again the results were the same. 
These conclusions do not in any way affect the question of the permanency of zirconia 
under the fierce heat of the oxyhydrogen flame; out such permanency, if purchased at 
the expense of inferior light, is too dearly bought, and will condemn the invention. Un¬ 
less the inventors are acquainted with some peculiarities of zirconia unknown to those 
who are 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 by lime, the zirconia-light, from an econo¬ 
mical point of view, is a failure. 
A few other experiments were tried, showing that soft lime and hard lime have to be 
placed at different distances from the blowpipe nozzle to get the maximum amount of 
light from each. Chemical composition, even more than hardness, varies the amount of 
whiteness of the light. Magnesia cylinders were found to take a longer time to heat to 
whiteness and a longer time to cool than either lime or zirconia. Quartz rapidly vitrified 
under the flame, and asbestos could not resist the intense heat. It requires time and 
repeated heatings and coolings to test the permanency of zirconia under the oxyhydro¬ 
gen flame to ascertain whether it does away with the necessity for clockwork apparatus. 
The piece used on Wednesday looked at the close of the experiments none the worse for 
VOL. XI. G 
