682
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.
J u l y , 1917
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERIiVG C H E M I S T R Y
TABLE 1-WATER-SOLUBLE
ARSENIC ON THE
A. 0. A. C. No. 3..
Method 24 hrs. a t 32' C.
. . . . . . trace
Devoe & Raynolds Boiling Method 4.62 0.47 0.06 0.46 0.23
CALCULATED
DRY BASIS
AS
A. 0. A.
PER CENT 4 ~ 2 0 ~
c.
Devoe&
YtkEd
Rg:itgds
No.
at 3 2 3 6. . . . . . . 0.56 7 . . . . . . . 0.23 8. . . . . . . 0.18
hfethod 0.68 0.30 0.21 0.33 0.46
There is no provision made for t h e removal of lead, as w e have never found water-soluble le,id in more t h a n traces in a n y sample of lead arsenate. Furthermore, as has been pointed out by Gray arid Christie, there is great danger of volatilization of t h e arsenic b y evaporating t h e solution t o sulfuric ;acid fumes, as t h e results given in Table I1 will show. The extractions were made by boiling as in t h e method given above. TABLEII-WVATER-SOLUBLE ARSENIC CALCULATED AS .&s2t3a BASIS Evaporated t o so3 fumes Reduced and Titrated without Evaporation.
683
ON
1x6 DRY
No. 1
. . . . . . . . . . . 2.40 . . . . . . . . . . . . . .3 . .56
No. 2
1.61 2.50
The m~ater-so~uble arsenic in commercial lead arsenate very often is largely in t h e arsenious form. Commercia1 sodium arsenate a n d arsenic acid often contain small amounts of unoxidized arsenic trioxide, and this precipitates with t h e lead arsenate in a form which is very difficult t o wash out with cold water, but which dissolves readily in hot water. This may be t h e reason why t h e boiling methods of Gray and Christie, a n d of t h e writers, and t h e hot water method of Robinson a n d Tartar' give higher results t h a n t h e cold a n d 32' C. methods of t h e A. 0. A. C. By t h e method given a determination of water-soluble arsenic may be made in less t h a n a n hour, which is a very important consideration for factory control work. The same method of extraction may be used for t h e determination Of Other water-so1ub1e impurities* D E V O E AXD
14-16 I
RAYNOLDS COMPANY
W E S T L A K E STREET, C H I C l G O
THISJ O U R N A L , 7 (1915), 499.
1
i
LABORATORY AND PLANT SAFEGUARDING THE EYES OF INDUSTRIAL WORKERS' T h e Seaman Gold Medal, gift of Dr. Louis Livingston Seaman, Trustee, is annually awarded b y T h e American Lluseum of Safety for progress and achievement i n t h e promotion of hygiene and t h e mitigation of occupational disease. This year t h e distinction of t h e Seaman Medal has been conferred upon t h e Julius King Optical Company, of New York, for scientific research and practical achievement in overcoming t h e harmful effects of ultra-violet and infrared rays of light in connection with arc-welding and other industrial processes a t very high temperatures. For a number of years t h e necessity of protecting t h e eyes of workers against chips of steel, splashes of metal and flying particles of emery, concrete a n d other materials, has been recognized, and t h e wearing of a n approved t y p e of safety goggles made compulsory. h far more insidious and hazardous danger t o eyesight is caused by certain invisible rays of light, such as t h e ultra-violet a n d infra-red rays. which are present in injurious quantities in t h e manufacture and working of iron and steel. These rays may cause electric ophthalmia. A4nylight source over zooo' Fahrenheit is a distinct menace and when a temperature of 6400' is reached, such as is encountered in electric carbon arc-welding, t h e volume of ultra-violet radiation is so great as t o impair vision permanently. On account of its destruction of animal tissue, these rays must positively be guarded against. Being invisible, their presence is detected by t h e operator only after h a r m has been done. Until a n investigation was made about three years ago, practically go per cent of all colored glass in goggles for industrial use was incorrect; a n d without a doubt a large number of blind men, or those unfortunates 1 Abstracted and adapted from the May, 1917, issue of ''Safely" (p. 118 and supplement), published by the American Museum of Safety, 14 t o 18 West 24th Street, New York City
who are afflicted with cataract, would have their full sight to-day if they had been provided with scientifically correct colored glass. One of t h e first forms of eye protection from glare was t h e wearing of blue glasses in t h e manufacture of steel, particularly in t h e open-hearth process. Glare is made u p of non-injurious rays of t h e spectrum, namely green, yellow, orange, and red rays. As a matter of fact, blue is one of t h e worst colors which could possibly be selected for this process, as it allows ultra-violet, violet, blue and also infra-red rays t o enter t h e eyes freely, cutting out only t h a t part of t h e light which is essential t o vision, but affording no protection from dangerous light. The higher t h e temperature, t h e more rich it is in ultra-violet rays. At t h e temperature encountered in oxy-acetylene welding and cutting, which is about 4350' Fahrenheit, grave danger exists and t h e glasses formerly supplied b y t h e oxy-acetylene companies, who manufactured a n d furnished t h e outfits, were without any scientific value whatever. They were using blue glass, as described, or else smoked lenses, which allowed a large proportion of injurious rays t o enter t h e eye. Where a wrong color is used a much darker shade is necessary t h a n if a correct color is prescribed. All colors have been analyzed a n d tabulated, by spectral photography, so t h e relative value of each is known. A temperature of zoooo requires a lens b u t slightly tinted, while a temperature of 6400' requires a lens so dark t h a t one can barely see t h e sun through it. T h e Julius King Optical Company has plotted all colors on a photometric scale, t h e standard adopted being a white cloud illuminated by t h e sun, which may be looked at indefinitely without eyestrain. A temperature of zooo' of molten iron through a slightly tinted glass has t h e same effect on t h e eye as if t h e
