1903.] KOENIG—ARTIFICIAL PRODUCTION OF CRYSTALS. 219 
death kindles our zeal to stop the spread of infection, to discover 
the means of preventing the suffering, and, when this is not pos- 
sible, to surround the lonely sick and dying with the best medical 
skill, attention and kindness that is possible. The desolation of 
their appalling loneliness is often doubtless greater than that of their 
illness and oncoming death combined.”’ 
PHILADELPHIA, April 4, 1903. 
ON ARTIFICIAL PRODUCTION OF CRYSTALLIZED 
DOMEYKITE, ALGODONITE, ARGENTODO- 
MEYKITE AND STIBIODOMEYKITE. 
(Plate V.) 
BY GEORGE A. KOENIG. 
(Received June 1, 1903.) 
In a paper on mohawkite, domeykite and other copper arsenides 
of the Mohawk mine (Zettsch. f. Krystall., etc., Vol. xxxiv, 1 Heft), 
I mentioned some attempts made by me to obtain domeykite in 
measurable crystals by the action of arsenic vapors upon metallic 
copper. One experiment gave crystals, although not measurable, 
but further trials failed at the time, evidently through my inability 
to maintain the proper temperature by means of an Erlenmeyer 
combustion furnace. The range between the temperature at which 
the crystals form and that at which the crystals melt is a very nar- 
row one. On the other hand the eagerness with which the copper 
absorbs the arsenic causes heat, and hence the difficulty in adding 
just the right quantity of thermal energy from the outside. It 
occurred to me to try an electric current as a source of heat. The 
very first trial gave most promising results. The experiments were 
taken up in November, Igoo, and continued until March, 1901. 
The adjoining figure illustrates the simple apparatus which proved 
itself adequate to all requirements. 
In watching the rapid growth of the crystals the similarity of the 
phenomenon with the development of an egg occurred to me, and I 
applied the name ‘‘ incubator’’ to the apparatus, than which no 
other could be more expressive. 
