414 Scientific Intelligence. 
7. On Crystals in Blowpipe Beads ; by Gzorcr H. Emzrson.—Obser- 
vations which I have made during the past year on the opacity produced 
by “flaming” in beads of borax, or microcosmic salt, when charged with 
certain substances, have established the fact that this opacity is due to 
the presence of crystals of a definite form, which varies with the sub- 
stance employed; and, also, that the same substance, in some cases, gives 
a different crystalline form with the different fluxes. The crystals are 
generally so minute as to require a good hand-lens, or even a compound 
microscope, to examine them advantageously ; and, in order to facilitate 
microscopic examination, the loop of platinum wire should be at least a 
tenth of an inch in diameter, and quite circular, and the bead very slightly 
convex. 
A little practice will enable the operator to regulate the density of the 
opacity—a very thin film, or cloud, extending partially over the surface 
of the bead, being all that is desirable. have found it convenient to 
alumina, glucina, zirconia, zinc, cadmium, bismuth, silver, tin, tungsti¢ 
acid, molybdic acid, protoryd of cerium, selenium and tellurium, 
With copper and uranium I have noticed what seems to be a ome 
T have, thus far, obtained crystals with baryta, strontia, lime, magnesia, 
way 
I have obtained a gray, metallic precipitate on the reheated portion of the 
ed 
surface of a borax bead, colored dark blue with oxyd of cobalt; 7 
. 
naked eye; but it is occasionally necessary to employ a magnifying power 
of one hundred and fifty diameters, or even more—to clearly distinguist 
able certainty the presence of two substances, so that they may both be 
recognized, as may be seen in beads charged with mixtures of tungst? 
and titanic, and tungstic and niobic acids. 
