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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
In order to obtain a more correct idea of the importations it is suggested that the figures for these two gums be added and classed together. The present Tariff Act went into effect October 3, 1913, so that it was natural that large quantities of chicle should he imported before that time. The new act pro-
vided for a duty of 1.5 c. per pound on crude chicle and 2 0 c. per pound on refined chicle while balata was admitted free. This no doubt resulted in the importation of some chicle under the name “Balata” and caused the drop in the chicle imports from 1914 to the year 1915. A t this point it is also interesting to note that exports of finished chewing gum to foreign countries have risen from $179,000 in 1914 to $574,400 in 1916. This has been shipped principally to England and Australia. A t a valuation of $o.do per lb. this would represent approximately 718,000 lbs. of chewing gum or x;g,ooo lbs. of dry chicle. The amount of chicle imported, manufactured and consumed in the United States in 1916 was approximately 7,031,000 lbs., equal to over 28,124,000 lbs. of chewing gum. This represents a national consumption of over 844 million packages per annum. THERUBBERTRADELABORATORY 325 ACADEMY STREET NEWARK,NEWJERSEY
REVERSION OF ACID PHOSPHATE B y CARLTONC. JAMES Received March 3, 1917
There seems t o be a n inclination of late among fertilizer a n d S t a t e control chemists t o d o more investigating of phosphates, their properties, a n d their effect upon soils a n d growing crops. Where State laws call for water-soluble phosphoric acid, careful investigation a n d attention is necessary, particularly in order t h a t t h e different brands may not fall below guarantee. A recent article in THISJ O U R N A L b y Mr. E. W. hiagruder’ recalled some work which was done by t h e writer in 1910, upon t h e reversion of acid phosphate by lime, a matter which has claimed t h e attention of chemists in t h e Southeastern states for t h e last two or three years. After having his attention called t o a fertilizer from San Francisco, which h a d evidently undergone reversion during transit t o t h e Hawaiian Islands, t h e writer undertook several experiments with different materials t o find t h e effect these had upon t h e acid phosphate of lime. T o 4 7 5 g. of acid phosphate in three separate bottles were added 2 5 g. lime (CaO), 2 5 g. unground coral sand a n d 2 5 e. unground brown guano, respectively; t h a t is, in each experiment there was added 5 per cent of t h e reverting agent t o t h e superphosphate, which we may consider a maximum amount t o use in practice. It should be explained t h a t t h e unground coral sand is carbonate of lime of 95 t o 98 per cent purity, a n d coarsely granular. T h e brown guano is a low-grade sandy phosphate from Laysan Island, formed b y t h e action of bird droppings upon coral sand with which it is intimately mixed. These mixtures were allowed t o stand 2 0 days, analyses being made of t h e water-soluble phosphoric acid from time t o time as other work permitted. T h e following table shows t h e water-soluble phosphoric acid found i n t h e mixtures at intervals after mixing. 1
THISJOURNAL, 9 (1917). 155.
TABLEI-PER
Vol. 9 , No. 7
WATER-SOLUBLE PHOSPHORIC ACID I N MIXTURES OF ACID PHOSPHATE WITH . . . . . . . .Lime (CaO) Coral Sand Brown Guano
CENT
... . . . . .. . .... . . .
5 Per c e n t . . On mixing., . . , , . . . . . . . . . After 2 d a y s . . . , , . . . . . . . . . . After 5 d a y s . . . . . , . . . . . . , , Aiter 12 d a y s . . ..... . . . . , . After 20 d a y s . . , , . , . . . . . .
21.37 20.83 20.18 19.69 19.12
21.37 21.08 20.75 20.59 20.51
21.37 21.24 21.16 21.00 21.00
This table shows t h a t superphosphate in which there is j per cent coral sand reverts 0 . 6 2 per cent in 5 days or 0 . 8 6 per cent in 2 0 days. With brown guano t h e reversion is not as great, while with lime it is 3 . 75 times as much. If then in a fertilizer guaranteed t o contain I O per cent of phosphoric acid water-soluble, we should have jo per cent acid phosphate of lime a n d 5 per cent calcium carbonate (coral sand), we should expect t o find after j days t h a t instead of I O per cent water-soluble phosphoric acid i t would contain only 1o-(o.62 X 0 .jo) = 9 . 6 9 per cent, t h e difference being caused by coral sand alone. I n order t h a t this fertilizer might show a I O per cent water-soluble phosphoric acid content after 5 days, 5 1 . 5 per cent acid phosphate would have t o be used originally. This example gives t h e effect of b u t one reverting agent, b u t i t is sufficient t o show t h a t quite a material allowance has t o be made in certain fertilizers t o cover reversion during transit. THE PACIFICGUANOAND FERTILIZER COMPANY HONOLULU, HAWAII
A RAPID METHOD FOR THE DETERMINATION OF WATER-SOLUBLE ARSENIC 1N LEAD ARSENATE B y H. A. SCHOLZ AND P. J. WALDSTEIN Received March 5, 1917
The method for t h e determination of water-soluble arsenic in commercial lead arsenate described b y Gray a n d Christie’ is very similar t o t h e method used by t h e writers for factory control during t h e past three years. T h e procedure follows: Weigh 0 . 5 g. of t h e dried and pulverized sample, or I g. of paste, into a 250-cc. volumetric flask. Add 2 0 0 cc. of recently boiled, distilled water and boil vigorously for 3 t o 5 min. Allow t o stand I O or ~j min., cool, make t o volume a n d filter through a dry paper. Ordinary, quickfiltering qualitative paper is‘used and there is rarely any difficulty in obtaining a clear filtrate. Measure zoo cc. into a 500-cc. Erlenmeyer flask, add a few crystals of potassium iodide a n d 7 cc. concentrated sulfuric acid, a n d boil down t o about 50 cc. Dilute with cold water, make alkaline t o methyl orange with sodium hydroxide, acidify with dilute sulfuric acid, and add a n excess of sodium bicarbonate. Titrate with N/20 iodine solution. This method was checked many times on lead arsenates of different compositions against t h e A. 0. A. C. method2 (24 hrs. digestion a t 32’ C.), a n d a few times against t h e Io-day method.3 T h e results always either agreed or came higher by t h e boiling method. Table I gives a few typical results. The arsenates of lead used included t h e products of several other manufacturers a n d represent practically every known commercial method of manufacture. 1 2 8
THISJOURNAL, 8 (1916), 1109. J . of A . 0. A . C.,1918, Nos. 1 and 2. Bureau of Chemistry, Bull. 107, Revised, p. 240.
