a and b, from urine and corn germ oil. It was later discovered that the synthetically produced lower acid derivatives of indole and naphthalene, though not chemically similar to auxins a and b, had an even greater effect on the growth of plants than the natural substances. In addition, while stimulating the growth of cambium in the higher plants, they inhibit the growth of the lower plant forms, killing off fungi and molds. Here we have the perfect agent for wound treatment-a combination fungicide and tissue growth stimulant. WILLIAMCOPULSKY 7901 FounTn AVENUE BROOKLYN. NEWYORK
Priorities
To tk Editor: I was very much interested in your editorial in the September issue as i t describes very closely the situation we find ourselves in here. We have now been refused small amounts of several kinds of materials without which we shall find i t difficult indeed to carry on efficiently with our instructional work. Foreseeing the situation early in the summer I began an active campaign on July 10. The Chemical Section of the O.P.M. on July 17 informed me: "You can be assured that the question of how to supply the laboratories of this country with much needed chemicals is receiving careful consideration.'' I was referred then to the O.P.A.C.S. and after being cut off from some materials I wrote again on August 22. In return a letter from another executive officer stated: "The program is being considered at the moment to take care of the institutions engaged in educational or research activities."
It seems to me that if this question has been under serious consideration since the 10th of Jn:y that i t is time something was'coming out of it. I am hoping that i t will not be necessary to resort to political pressurealthough that seems to be the most fruitful approach in Washington. I hope, therefore, that you will be able to keep this matter actively before the people and count us in to help in any way possible in bringing i t forcefully to the attention of the proper authorities. In my opinion it will be only a short time before rubber and cork will be under priorities and when this happens some of us will have to close up shop. E. C. GILBERT
To the Editor: If you continue to campaign to relieve the difficulty of chemical laboratories in obtaining certain supplies and materials, we hope that you will accept our support for the campaign.
We have encountered some difficulty in having our requisitions filled and were particularly disappointed last year when we were unable to obtain a new distilledwater line for our laboratories because of the priority pertaining to any aluminum usage. We hope that a sufficient number of laboratories will also support your efforts so that there may be a campaign of sufficient strength to accomplish something. J. W. NECKERS SOUTHERN ILLINOIS NORMAL UNIVERSITY CARBONDALE, ILLINOIS
Preparing Dry Ammonia To the Editor: I read with interest G. M. Lisk's article in the July, 1941, issue of the JOURNAL OF CHEMICAL EDUCATION concerning a "Demonstration Involving Air Pressure" in which he suggested the preparation of ammonia by "boiling concentrated ammonium hydroxide and passing the gas through Drierite." A more convenient and probably quicker method of getting dry ammonia for this experiment, and others like the ammonia fountain, is that of dropping concentrated ammonium hydroxide through a dropping funnel onto dry sticks of sodium or potassium hydroxide and collecting the ammonia by downward displacement of air. This reacts by the common ion principle and is one of the handy tricks some of us learned from our good Professor Bean, Columbia University. WALTERQ. BUNDERMAN HIGASCHOOL JOHN HARRIS H ~ s ~ r mPENNSYLVAN~A o, Concerning the Statics of the Balance B e a m
To the Editor: Your suggested note' on the Moyer article is acceptable to me. If we use the formula
in which K is the pendulum leg of the beam, and H the difference of level of the knife edges, i t can be seen that K is measured, not to the face of the edge, but to its center of curvature. H is affected to some extent by friction, or more probably by progressive distortion of the agate with added weight. This distortion appears as a rounding of the edge in the observations. Added to this, the bending of the beam may cause a variation in the difference of level, so that the results are variable within small limits. The radius of curvature of the knife edge may be as much as one-fifth of the leg of the beam. For practical purposes, however, the formula can be used as i t stands to show the working condition of the balance. ARCHIBALD CRAIG Mans, PENNSYLVANIA See page 546.
