This investigation shows that there are many insecticides on the market which are nearly worthless, and many for which a very exorbitant price is paid that could just as easily be prepared at home. In fact there are very few of the above insecticides which could not either be prepared at home or for which a substitute could not be prepared at a less cost. The only way to obtain information regarding insecticides is by consulting bulletins dealing with the subject, or in case the composition of the insecticide in question is not published, to have the same analyzed. CORRESPONDENCE WITH MANUFACTURERS. In order that manufacturers might have a chance to comment upon analyses before they were published, the following circular letter was sent to each manufacturer whose goods had been examined: U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY, DEAR SIR: The Bureau of Chemistry is preparing a bulletin giving the results of its examinations of insecticides and fungicides. While we feel sure that the data are practically correct, at the same time we know that one sample does not always represent the products of its manufacturer. We should, therefore, be pleased to have you make any comments that you think necessary on the data as given below. It might be as well for you to know that in our forthcoming bulletin this Bureau has expressed an opinion in favor of a 6 per cent rather than a 4 per cent limit for soluble arsenious acid in insecticides containing this substance. Respectfully, H. W. WILEY, Chief. The answers to the above letter, where they throw any light upon the subject under consideration, are as follows: [Serial No. 19625.] We note that the analysis of our Green Arsenoid shows 2.02 per cent sodium sulphate and 1.30 per cent sand, and we wish to explain that the sand gets into this material from the arsenic which is used in its manufacture. We have been using English arsenic, which at times contains quite a percentage of sand. This does not seem to be the case with the Continental arsenic, which we are now using exclusively. The sodium sulphate is, of course, a by-product, and the quantity in the arsenoid is dependent, in a large measure, upon the amount of washing that the arsenoid receives. We believe that the 2.02 per cent is quite exceptional, particularly in view of the fact that we are now washing the arsenoid more thoroughly than heretofore. ADLER COLOR AND CHEMICAL WORKS. [Serial No. 22287.] We are in receipt of your analysis of White Arsenoid and would say that this substance is a product which we had used only in a tentative way. There is now none on the market and will be none in the future. ADLER COLOR AND CHEMICAL WORKS. [Serial No. 2, I & W.] Following is the synthesis of the insecticide, which we have been as careful as possible not to deviate from in compounding: Comment by chemist: The best method available for determining camphor gives very low results, but we are sure that our nicotine figure is correct for the sample examined. [Serial No. 19530.] We have the report on sample 19530, and would say that while we have always been aware that the powder in question was colored, there being a demand for this grade, we had no idea the quality is not of the best. [Serial No. 20456.] Z. D. GILMAN. I notice the large amount of moisture. The original soap, which was an experiment, had about this amount, and the soap that I have been sending out for a long time should have less. JAMES GOOD. [Serial No. 19690.] One-thirteenth part of the total weight of Grape Dust consists of tobacco. BENJ. HAMMOND. Comment by chemist: Another sample of Grape Dust was obtained directly from the manufacturer and analyzed. It was found to contain about the same amounts of sand, copper oxid, and gypsum as the previous sample, but the sulphur figure was 52.82 per cent and the tobacco figure 8 per cent. Scrofularia consists of per cent oil of cedar oil. [Serial No. 19681.] pyrethrum, napthalene, tobacco, camphor, and about 0.1 We never put in any lead chromate at all. BENJ. HAMMOND, Comment by chemist: In the sample of Scrofularia examined in this laboratory pyrethrum and tobacco only were found, consequently upon hearing from Mr. Hammond a fresh sample was at once obtained from him, in which were found all the ingredients he mentions above, excepting oil of cedar, which was present in such small quantities that we were unable to find a good test for it, mixed as it was with the other constituents. In the sample originally examined the camphor and napthalene had entirely volatilized. Mr. Hammond was informed that whoever was supplying him with pyrethrum was coloring it with lead chromate. [Serial No. 19524.] The arsenic percentage is above any we have used in many years. formula is now under 1 per cent. Our working BENJ. HAMMOND. [Serial No. 6 I & W.] I use a high-boiling paraffin oil, but have never used turpentine. I have sent you by mail a sample of my insecticide and disinfectant. HEINE CHEMICAL Co. Comment by chemist: The sample sent by the Heine Chemical Company was received and analyzed and found to consist principally of one of the higher-boiling petroleum oils and sassafras, but the same was very different from the original sample analyzed, which evidently consisted of kerosene and turpentine. A sample of the oil was sent to Mr. Heine, stating the facts, and suggesting that perhaps someone was putting up goods under his name, since every test showed that turpentine was present. To this no reply was received. [Serial No. 22292.] Lee's insect powder contains one more ingredient not mentioned here. GEO. H. LEE CO. [Serial No. 19627.] Lee's Lice Killer is a coal-tar product heavily charged with gases destructive to insect life. It can not be prepared of uniform strength and quality from bulk material obtained in open market, but requires fresh and uniform ingredients, special manipulation, and air-tight packages. [Serial No. 19680.] GEO. H. LEE Co. We use the best and finest ground tobacco dust and lime chemically treated with the higher products of coal tar. If there is any sand in the mixture it goes in before the goods reach our hands. [Serial No. 19533.] D. J. LAMBERT. You are correct in your surmise that one sample does not always represent the product of its manufacturer. We do not think that this can possibly be an examination of our standard article on account of the large percentages of acetic acid and soluble arsenious oxid. JOHN LUCAS & Co. Comment by chemist: An examination of a sample forwarded by Mr. Lucas was made with the following results: Soluble arsenious oxid..... 5.33 This showed that Mr. Lucas had improved his process since making the sample, the analysis of which has already been given. [Serial No. 19617.] We have ceased to manufacture this article. THE NICHOLS CHEMICAL Co. [Serial No. 20458.] I should judge the sample you had must be an old one from the small percentage of water present. How there should be such a large amount of unsaponifiable matter I can not understand, unless the presence of petroleum has acted on the fatty acids used. When the soap is made a mixture of fat oils and resin is saponified nearly neutral and 25 per cent of the entire weight of the finished mass in kerosene oil is added. You may have had some of the crude oil soap which had 25 per cent crude Pennsylvania petroleum in it. POOLE & BAILEY. Comment by chemist: The sample examined so evidently consisted of soap and unsaponifiable matter, resembling paraffin, in the proportions given in the table, that a sample was forwarded to Poole & Bailey for analysis if they so desired. No reply was received. [Serial No. 22289.] This material should average 30 per cent nicotine. [Serial No. 20482.] SKABCURA DIP Co. We use the best commercial white arsenic. Some few years ago we used one-third barium carbonate; now we use one-seventh barium carbonate, and we shall soon discontinue it altogether. E. S. WELLS. [Serial No. 13 I & W.] Chloronaptholeum is prepared from coal-tar creosote, which is obtained by fractional distillation of coal tar. After all the light oils have been distilled, they are collected separately and cooled by means of refrigerators, and then redistilled until all the impurities and free carbon have been eliminated. The oil has then the required specific gravity, and is free from carbolic acid. It is then treated in the presence of resin and fatty matter by means of alkali, containing a certain percentage of sodium chlorid, when a light-brown finished fluid is obtained. WEST DISINFECTING CO. Farmers and others desiring to have work done similar to the above should apply to the Bureau of Chemistry, laboratory of insecticides and agricultural waters, U. S. Department of Agriculture, Washington, D. C., for directions for taking and forwarding samples. |