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INA TOT 
[| Fan. 6, 1870 
of chromium is produced at a very high temperature, and at the 
same time, a flame of such extraordinary chemical power, that 
chloride-of-silver paper held at a distance of twenty centimetres 
(eight inches) blackens sensibly in thirty seconds, or about as 
quickly as in full daylight. The same experiment may be con- 
ducted with equal success with chloride of titanium, which gives 
a blue flame of extraordinary chemical power. Unfortunately, 
these chlorides can be manipulated only by persons well versed 
in scientific research, as they become decomposed under the in- 
fluence of moist gases, and the lamp then emits a considerable 
amount of vapour, as in the case of metallic magnesium. Mag- 
nesium, chromium, and titanium, all of which exist in the sun, 
are the sources of light most suitable for the purpose. The 
author is at the present moment occupied in establishing 
the coincidence of the ultra-violet rays of the spectrum 
with those of these metals. For the purposes of photo- 
graphic enlargement, the author uses the Drummond system, 
substituting for the cylinder of lime, one of very pure 
carbonate of magnesia, free from soda, baryta, and iron, 
either alone in a very compressed state, or containing titanate 
of magnesia obtained by a mixture of chloride of titanium 
and carbonate of magnesia. The pillars are square at their base, 
three centimetres in diameter, and eight in height ; they burn for 
an hour and a half, and cost less than half a franc apiece. They 
emit a very brilliant and economical light. Instead of pure 
hydrogen gas, ordinary coal gas, or even alcohol, together with 
oxygen, may be used. The preparation of oxygen, on the 
author’s plan, is very easy, and free from danger. He employs 
for the purpose calcined oxide of manganese ; it is then finely 
powdered and passed through a sieve. The chlorate of potash 
he uses is also pulverised and sifted ; 600 grms. of brown 
manganese and 1,200 grms. of chlorate are well mixed by hand 
in an earthen vessel and sifted, care being taken not to allow 
any organic matter to enter, and the whole is then introduced 
into the wrought-iron retort A (fig. 1). The cork stopper E, 
covered with tinfoil, is put into its place, and the junction F, 
Fic. 1. 
which places the retort, by means of the leaden pipe G and 
rubber tube I, in communication with the gas-bag, is adapted. 
The delivery tube (I) should be of at least half an inch internal 
diameter, and the wash-bottle H must be half filled with 
water. Asmall quantity of ignited charcoal is thrown into the 
little furnace B C, or a gas jet may be used, and after the lapse of 
a few minutes the india-rubber bag begins to inflate, and in twenty 
minutes it is full of oxygen ; it is necessary during this operation 
to remove the weights and pressure-boards from the top of the bag. 
When the operation is finished and the retort somewhat cooled, 
the junction F is unscrewed, the cork E taken away, and warm 
water poured in until the retort A is filled. The water is 
allowed to remain for an hour, and the contents are then poured 
into a large jar, where, after the lapse of an hour or so, the 
oxide of manganese subsides. The clear water is decanted off, 
and the black deposit put upon a plate near the hearth to dry, 
after which it is again ready for repeated employment as often as 
desired. With ordinary native manganese a much higher tem- 
perature is necessary, the mixture having a tendency to puff up, 
and the operation becomes dangerous. For this reason it is 
advisable to use a cork stopper, E. A kilogramme of chlorate 
of potash yields 270 litres of oxygen, and this quantity will supply 
the lamp fortwo or three hours; thus the cost of our light, includ- 
ing coal-gas and the magnesia, amounts to two francs per hour. 
The oxyhydrogen burner used (shown in figs, 2 and 3) is very 
CGC nn | r i 
i 
Fic. 2 Fic. 3 
convenient. Those who haye gas laid on in their houses will 
use the apparatus with two jets of gas (fig. 2); others will find it 
more expedient to employ the spirit-lamp arrangement (fig. 3). 
In both figures the same initials refer to similar details ; A is the 
pillar of magnesia fixed upon a stem, B, which may be turned, 
lowered, or raised upon the rod C. EF is the stand or support, 
and G the pinion by means of which the light is adjusted in the 
centre of the apparatus. The jets for the two separate gases are 
formed by two concentric tubes, R, ST, sliding at S, so that the 
upper portion of the tube ST may be raised when it is desired 
to heat the top of the magnesia pillar A. Two stopcocks, O, P, 
lead the gases into the apparatus, the letters H and O being 
marked upon them to distinguish the oxygen supply-tube from 
that of the hydrogen or coal-gas. By means of a screw, I, the tubes 
Rk, ST, may be approached to, or removed from, the magnesia 
pillar. The coal-gas does not mix with the oxygen, excepting in 
the flame itself. The manner of employing the apparatus is 
exceedingly simple. The tube and stopcock marked H_ (con- 
nected with the supply of coal-gas), is first opened and the gas 
ignited ; the stopcock marked O (in connection with the bag of 
dl 
vn 
Fic. 4. 
oxygen) is also opened, and the tube B then raised in such a 
manner that the top of the pillar A is heated by the flame, the 
extremity of the tube T being brought almost into contact with 
the magnesia. The heat soon indents the pillar, and 7 7s only 
when a cavity has been formed that the light attains tts highest 
