VOL. 2, No. 9
SAFETYFIRST IN STORING CHEMICALS
783
shavings or fine planer chips will also ignite with great violence on addition of a drop of water. This shows the danger of dispensing sodium peroxide on filter paper, and the danger of stowing it away in wooden lockers where it may get wet. A pile made similarly will be set on fire by the stream of sulfur dioxide from a tank of this gas. It is a crime, I am told, punishable by fine of $30.00, in a certain laboratory to put a piece of charcoal into a locker. This is a wise and necessary precaution on the part of those in charge for nothing holds the heat like charcoal and it is nearly impossible to tell when the fire is all extinguished on it. Carbon disulfide is so easily inflamed that on one occasion we had a can of it take fire as i t was being siphoned through a rubber tube. No flames were near and the only explanation we have is that i t became electrified and a spark jumped into the vapor. Such a substance as zinc ethyl which is spontaneously inflammable should by all means be kept where, if it lights, it can do no harm and only small lots of it should ever be on hand. There is probably no new chemistry here for any who will read it, but possibly the thought of safety in storage will be quickened by those who try out some of the demonstrations here recorded.
X-Rays Will Speed Laboratory Analyses. Rapid anal&s of materials in the labaratory by the use of X-rays in a much shorter time than required by the older chemical methods, is promised by Prof. Urhain, of the Minero-Chemical Laboratory a t the ~ o h o n n e . With the assistance of Eugene Delaunay, he has just completed a series of tests of the X-ray method. The apparatus used is composed of an X-ray tube; a lead screen in which a small slot has been pierced; a "selector" of tantalum, as a filter for the rays; a stand to hold the ~ i e c to e be studied: and a detector t o measure the intensity of the radiation received -the inrcnsity I,emg indir:$ted by the diq,laremmt of :an i l l u r n i n ~ t d..pot The rnntrrial to he an;dyrrd is placed in the henm, and whcn it is in good condition, the spat of light remains stationary; but if a fault in the material appears, the electrometer registers promptly. By recognized laws of physics, the deviation is proportionate t o the amount of the fault in the matter. By this method, the smallest faults can be detected. For actual quantitative work, the movable holder for the material is replaced by a small basin. By using, for example, distilled water as a base, and placing this first in the basin to set the "zero starting point," other solutions containing salts can be analyzed by straight calculations. For more than one salt in solution, more than one wave length can be used. The great advantages of this would be first for the speed of analysis, and second that a constant watch and check can be kept on the material used in manufacturing. M. Delaunay, who did the actual work, also says t h a t there is no risk of error, which greater accuracy should prove invaluable.-Science Senice
