May,
1912
T H E J O U R N A L OF I N D U S T R I A L A N D ENGI-VEERI.VG C H E M I S T R Y .
387
NOTES AND CORRESPONDENCE THE PAINT AND VARNISH INDUSTRY. Edztor of the Journal of Industrtal and Engzneertng Chcniirtry: A recent editorial, in THISJOURNAL, on the condition of the paint and varnish industry appears to the writer to leave out of account certain important facts. I n the first place, this industry, as a whole, is in a depressed state, due primarily to the advanced prices of materials. Repeated failures of crops of flaxseed have produced a high, and a t the same time, fluctuating price for linseed oil, which, whatever may be the merits of the matter, is the only oil having popular confidence; China mood oil has special uses, but does not affect the price of linseed, and is, in fact, more costly; and there is a tendency the world over toaard an increase in the price of lead and zinc, which are the bases of the only pigments that have any TI hite color value. The turpentine dealers’ corner which put up the price of t h a t product last year undoubtedly caused many to begin using mineral substitutes, and this has been helped by the high price of everything else; but if oil becomes cheap again, which will probably occur sometime, the increased use for turpentine will send its price up; this will inevitably happen from the lessening supply in any case. The failure of the Navy Department to purchase seventy thousand dollars’ north could hardly have affected the market, as it is less than I per cent. of the amount exported-except that it has been used as an advertising item by the makers of substitutes. The same is true of the increased use of barytes and other cheap pigments by the Navy. The fact in regard to these is that the experts of the Bureau in charge of supplies have long complained that commanders of ships paint their vessels more often than is required for adequate protection; ten t o fifty or more coats of paint are removed when a ship is repaired. This may be said to be a waste of paint; but the captains say that universal experience, both a t home and onforeign ships, shows that a condition of absolute freshness and spotlessness is necessary for the maintenance of proper discipline, and the real use of paint is to keep the ship looking smart. Now the supply department says. “Very well, we will furnish as cheap a paint as possible that will look well when new, if it becomes brittle and scrapes off easily-, so much the better.” So they are doing as Mr. Toch says; and it is certainly a defensible position. It is not an economic problem a t all; it is one of fighting efficiency. When it is a question of getting the most protective value for the money, as in painting the Capitol and other United States buildings a t Washington, they are painted with straight corroded lead and linseed oil, exactly as they have been for a hundred years past. Mineral oil substitutes for turpentine are much better than formerly; Chinese mood oil has made a strong and independent position for itself in the varnish business; but if linseed oil were to be sold a t 5 0 cents per gallon, all the so-called substiin all tutes for i t would disappear. Such substitutes-not cases the same ones-were used more extensively twenty years ago than now; they will always be used to some extent. In limited proportions some of them have great value for special uses; but in a large way the present condition of this industry is affected by natural and general economic conditions far more than by changes of a merely technical character. The tendency is constantly increasing to regard the unrestricted use of substitutes in the paint trade as a source of danger, and to more specifically define their legitimate uses, this, as in all other lines, involves contraction rather than A. H. SABIN, expansion. April 12th.
DETERMINATION OF MANGANESE IN STEEL.-A
NOTE.
Editor of the Journal of Industvial altd Engineering Chemistry: In the March issue of THIS JOURNAL for the current year there appeared an article entitled “ Determination of Manganese in Steel,” by James J. Doyle. The writer turned to this article in expectation of finding the description of a new method for the determination of this element, but after reading the method, was surprised that it should have been published THIS JOURNAL, as it is essentially the same as published by Stehman in the Journal of the American Chemical Society, 24, 1206(1902), or ten years previously, and other points in the article were covered in my remarks on Stehman’s method, 1’01. 2 5 , 392 (1903). Yours very truly, H.E. WALTERS. March 30, 1912. I.
APOCYNUM OR INDIAN HEMP, RUBBER.’ B y CHARLES P. Fox.
.4pocj’naLm Hypercifolium (Nat. Order, Apocynaceae) is an indigenous plant common to many sections of the United States. It is a strong rooted perennial with reddish stem, fibrous bark, long, slender seed pods, seeds with long, white, cottony appendages, and a milky juice. The latex is white, viscous, neutral or slightly alkaline, and has the strong acrid odor peculiar to the plant. The usual coagulating reagents react with this latex in the following manner: Acids do not coagulate; latex becomes thin. Alkalies do not coagulate; restore the viscosity; change the color from white to brownish yellow. Boiling coagulates slightly; action slow. Acetone (l/,,, volume) coagulates immediately and completely; liquid is colored chocolate-red. Formaldehyde coagulates readily but is much slower in action than acetone. Phenol coagulates the latex, but gives a soft product. Salt solution coagulates slowly, giving a finely divided precipitate hard to coalesce. Boiling the same solution gives a soft product. Of the above methods, the use of alcohol or acetone, and formalin are the only ones recommended. Of these two, acetone is preferred. The latex of Apocynum differs slightly from that of Asclepias in that i t coagulates spontaneously, even if it is kept in closed containers. The naturally coagulated latex gives: Liquid portion. . Cheese (wet).. . .
. . . ..... . . . . . .. . . . . . . . . ,
Per cent. 67.58 32.42
The liquid is white (not clear), slightly acid and with the characteristic acrid odor. This liquid failed to coagulate after addition of more acid. Slight excess of alkali increased its viscosity and changed its color from white t o brownish yellow, but did not precipitate or coagulate it. Boiling had no effect. Excess of acetone gave a finely divided precipitate, the particles of which were not cohesive. Evaporation of the mixture, after washing with water and treatment with boiling acetone, gave a small quantity of a black, soft rubber destitute of strength. The cheese was composed of: 1 Presented before the Rubber Section, A. C. S., at forty-fifth meeting. Washington, December, 191 1 .
