Zirconia for the Oxy-hydrogen Light. 213 
tilled water well stirred, and when the precipitate has settled it 
is collected on a filter as before and allowed to drain as long 
as it will yield any fluid. 
th. The precipitate obtained above is dissolved in as little 
pure hydrochloric acid as possible, the solution diluted with 
distilled water to five hundred cubic centimeters and heated to 
_ boiling for some time. Ammonia is added to the hot solution, 
when the zirconium oxide is thrown down and is to be col- 
lected on a filter, washed with hot water and allowed to dry at 
the temperature of the air, the yellowish or whitish lumps 
resulting are pulverized in an agate mortar, when a white 
powder is obtained. The quantities I have given in the ’ 
various operations detailed above apply to two grams of the 
powdered zircon. For the preparation of a zirconia cylinder of 
sufficient size the product obtained from four grams of zircon 
is required, the quantities may be doubled throughout; but, it 
is better to make two fusions of two grams each and double 
the quantities given in the latter part of the description. 
I have also tried the separation of zirconium chloride from 
iron chloride by hydrochloric acid; but, though I worked at a 
temperature of 32° F., the yield was very small and therefore 
unsatisfactory. In the process by hyposulphite of soda I 
found it very difficult to get rid of the soda. The process of 
disintegrating the zircon by chlorine at a high temperature 
also failed to give satisfactory results in my hands, and I find 
that Dr. Melliss records the same experience. : 
Preparation of the Cylinders. 
The zirconium oxide powder obtained in the manner described 
b 
above is to be heated in a platinum crucible and kept at a 
bright red for five or six hours; it will under these circum- 
stances shrink considerably in volume. I have sometimes in 
addition submitted the powder to the heat of the oxy-hydrogen 
flame with advantage, spreading it out for this purpose on a 
piece of platinum foil supported on a slab of iron, and directin 
the flame on the powder. The operator should wear smoke: 
lg The powdered oxide thus condensed by heat is 
then moistened with just enough water to give it a tendency to 
form small lamps. In this condition it is placed in a cylindrical — 
mould and submitted to severe pressure by a piston fitting 
closely to the cavity of the cylinder, both of which should b 
properly oiled. The size of the pencils I have prepared is 
about six millimeters in diameter and one centimeter in length. 
When in use they are mounted so as to present one end to the 
action of the oxy-hydrogen flame, when a brilliant circular 
Spot of light is formed admirably adapted for all kinds of 
optical experiments. 
