168
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
the gaseous state and mixed with an oxygen-containing gas mixture, to the action of vanadium (molybdenum) oxides heated to temperatures ranging from 250” to 650” C. When the process is carried out according to the above claims either on a laboratory or commercial scale, phthalic anhydride is produced which may consist of long, glistening needles, but it is always far from colorless and anything but substantially chemically pure, and having a melting point above 130’ C. (corrected). The color ranges from a light yellow to black and the melting point never is as high as 130’ C. There is no mention made in either of the Gibbs-Conover patents as to the purity of the product, but Gibbs bases the disclosure of the remarkable purity of the product on Monroe’s work and an article published by him.’ It has been shown that Monroe carried out his work with material made according to U. s. Patent 1,336,182, which is the one under discussion. The article entitled “Phthalic Anhydride. I-Introduction,” just mentioned, was received for publication August 19, 1919, which was approximately two months earlier than the filing date of U. S. Patent 1,336,182. I t will be evident to those who have had charge of similar problems that two months is a very short time for the development of a manufacturing process for the product in question. In addition to this it can be definitely proved that this product was produced according to the claims of the patent in large quantities a t a much earlier date than either of these disclosures. It is evident also that Gibbs has neglected to consider the judgment reached by the examiners of the Patent Office after a very careful search of the Patent Office records as well as the literature on the subject. In view of the above facts i t does not seem impossible to conceive the grounds upon which such a patent was granted. C. E. ANDREWS TRBSELDENCOMPANY PITTSBURGH, PA.
November 15. 1920
THE IGNITION OF FIRE ENGINE HOSE WHEN IN USE Editor of the Journal of Industrial and Engineering Chemistry: Boston papers of November last had a most astonishing tale of the spontaneous ignition of fire hose when in service. The facts in the case are as follows: It was a new 50-ft. length of the usual 2.5-in. hose consisting of a simple rubber lining inside a heavy cotton jacket. Outside this was drawn a similar cotton jacket. The hose was used in a test made on the new pumping engines, and the stream was throttled down about 45 per cent, discharging about 250 gal. per min. Notwithstanding the fact that this quantity of cold water from the Charles River was used, the hose took fire between the cotton jackets. A spot 2 in. long by 1.12 in. wide was burned clear through each. Careful examination reveals the fact that on each side of the burned hole the inner casings or jackets are very severely chafed. This chafing coming from the vibration produced in the hose by the pump was in my opinion, sufficient to produce great heat and finally active combustion. I found also a similar state of things in another sample of hose used at a later test. The chemical composition of the rubber, in my opinion, had nothing to do with the case. I am of the opinion that the occurrence was due to excessive friction between the cotton casings produced by the vibration of the hose in service. It is interesting t o note that these results have been confirmed by ILlr. J. s. Caldwell, chief engineer oE the N. E. Insurance Exchange, with three different types of engines and three different makes of high-grade, standard hose. The experiments were made in Portland, New Bedford, and Boston, and in some cases the cotton was charred in about 15 min. MASSACHUSETTS INSTITUTE OF TECHNOLOGY A. H. GILL, CAMBRIDGE, MASSACHUSETTS January 13, 1921 1
THISJouarnl~.11 (1919). 1031.
Vol. 13, No. 2
REPAIRING IRON LEACHING VATS Editor of the Journal of Industrial and Engineering Chemistry: Herewith I should like to communicate an experience in repairing leaching vats which may be helpful to others. The bottom of a 5.5 f t . by 22 f t . circular cyanide leaching vat contained numerous holes, and some parts were so badly worn out that a needle could be passed through without effort. At first the leaks were calked with coal-tar soaked cotton waste. This method proved to be inefficient. Then a 2-in. cement bottom was laid on the inside af the tank, but pressure variations during charge and discharge, causing various bendings of the bottom, broke the cement layer in no time. This observation led to the construction of a more flexible bottom, built as follows: Over the whole defective bottom was laid a 0.25-in. asphalt layer, covered with a layer of canvas (in our case old filter leaves). Care was taken that the canvas was pressed on the asphalt while the latter was still hot, in order to secure a close contact. Finally the canvas was covered with asphalt 0.25 in. thick. After 24 hrs. the tank was filled with water, held under water pressure for 72 hrs., discharged, filled again, and held under pressure again for 72 hrs. During this experiment not the slightest leaking could be observed. The total repair cost amounted to approximately $92, whereas a new tank was quoted a t $750. To put a new iron bottom in was impossible, owing t o the fact that the bottom ends of the mantel-pieces would not stand a new riveting. As your Journal, which I receive as a member of the AMERICAN CHEMICAL SOCIET:TY, often gives me helpful suggestions, I should like to help someone who is in trouble. C. FLURY FRENCH MINES TAIYUDONG, KOREA, JAPAN October 13, 1920
VAPOR COMPOSITION OF ALCOHOL-WATER MIXTURES Editor of the Journal of Industrial and Engineering Chemistry: Under the above heading in THISJOURNAL, 12 (1920), 296 W. K. Lewis disposes of the writer’s earlier results on the same subject [THIS JOURNAL, 8 (1916), 2611 with the statement that “The work of Evans is obviously unreliable in view of the fact that he finds the composition of vapor and liquid identical a t 92 per cent by weight.” This statement of Lewis is incorrect, as the writer’s experiments did not extend beyond 91.1 per cent in the liquid, which corresponded to 91.8 per cent in the vapor. In correspondence Lewis says that he obtained the “92 per cent” by slightly extending the writer’s curves beyond the experimental regiongraphic extrapolation. In view of the admitted experimental error of possibly 1 per cent and the absence of evidence of the character of the curves beyond this region, this is manifestly unjustified, especially as the writer expressly accepted 96 per cent alcohol by weight, as found by others, 3s the constant boiling mixture. Lewis’ results are not experimentally obtained by him, but are graphically extrapolated (again) by him from experimental results of Wrewsky, the extrapolation being for as much as 25” beyond the actual observations! Surely experimental confirmation of results obtained in this way might be expected, and would be more convincing than Lewis’ belief that they are “by far the most accurate available.” A comparison of the curves obtained from Lewis’ extrapolated and the writer’s experimental results, pIotting alcohol per cent against boiling point, leaves the probability in favor of the writer, as judged from the form of the curves, especially for boiling points between 90’ and 97’, where they most diverge, Lewis’ curve showing an improbable bulge in this region.
,
