OCt., I913
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
t h e many varying degrees of shade which are demanded by t h e trade in these products. Here are found electric stirring devices, balances, facilities for volumetric analysis a n d t h e matching of colors. Adjoining t h e oxide room is t h e sample room where samples of raw material, fuel a n d fluxes used in t h e formulation of charges, by-products a n d t h e finished products are carefully tabulated. The assay room, equipped with muffle furnaces for t h e determination of gold a n d silver values in ores a n d
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essential requirements for t h e development of negatives. T h e walls throughout all t h e building have been plastered a n d painted with white laboratory enamel unaffected by gases, giving a surface easily washed a n d of maximum light. The lighting system has been specially designed b y t h e General Electric Company, t h e tungsten method of lighting being adopted. The heating of t h e building is effected by t h e hot water system.
DARK ROOM
SECOND FLOOR PLAN
finished products, completes t h e plan of t h e ground floor. I t will be seen t h a t every facility for general routine work in t h e examination of lead a n d its compounds has been given by t h e above plan. On t h e second floor, devoted exclusively t o research work, are found t h e research laboratory, t h e office, library a n d photomicrographic room. The research laboratory is fully equipped for investigation work on glass, rubber, paints, varnishes, a n d t h e s t u d y of new processes together with manufacturing problems. Standard equipment of modern types is available for t h e investigation of a n y new practice o n a scale which will permit of t h e establishment of d a t a capable of being used directly on a commercial basis. Ample facilities are provided for t h e s t u d y of oils by t h e use of t h e viscosimeter a n d refractometer, together with t h e examination of *the many different compounds through t h e spectroscope. The most improved methods for t h e testing of white paints for color a n d strength have also been installed. The photomicrographic a n d microscopic s t u d y of paint films a n d dry pigments, which has of late years become of such importance, is fully provided for in the d a r k room equipped with low a n d high power microscopes, photomicrographic a p p a r a t u s a n d a l l
The erection and equipment of this laboratory, complete in every detail, is only another instance of the stress which is laid upon research work a n d routine work, leading t o t h e accurate control of manufacturing processes by t h e present-day manufacturer. JOPLIN,Mo.
A SIMPLE GASOLINE GAS GENERATOR FOR SULFUR DETERMINATIONS' By C . E. WATERS Received August 7 , 1913
One of the recognized sources of error in t h e determination of sulfur a s barium sulfate is t h e taking u p of sulfur dioxide a n d trioxide from t h e products of combustion of t h e gas flame. The writer has repeatedly noticed drops of fairly strong sulfuric acid on t h e underside of platinum dishes in which solutions have been heated for a few hours b y a gas flame a n inch or so in height. On one occasion a watch glass filled with water was placed over t h e mouth of a 2-liter flask containing water. After heating over a gas flame for a comparatively short time, t h e water in t h e watchglass gave a turbidity with barium chloride. It has also been found t h a t t h e dark deposit, commonly regarded as soot, which is found on t h e bottom of a flask heated on iron gauze, contains a sulfide which 1
Published by permission of the Director of the Bureau of Standards
T H E JOURIZ’AL O F I N D C S T R I A L A Y D E S G I S E E R I - V G C H E M I S T R Y a t once dissolves in dilute evolution of hydrogen sulfide. The amount of sulfur t h a t solution in a covered beaker of barium sulfate cannot be
hydrochloric acid with would be absorbed b y a during t h e precipitation very large a n d m a y be
negligible, b u t this possible source of error should be eliminated in careful work. Ordinarily solutions t o which barium chloride is t o be added can be heated most rapidly a n d conveni,ently on t h e steam bath, a n d only a few minutes’ heating over t h e flame is necessary t o bring t h e m t o t h e boiling point. If, however, a fusion is required t o transform t h e sulfur into a soluble sulfate, a n d especially if t h e melt must be stirred, t h e danger of contamination becomes serious. Placing t h e crucible in a hole in a n inclined plate of asbestos board m a y prevent access of gases from t h e flame, b u t there is always danger t h a t particles of gypsum from t h e board may get into t h e melt. An ordinary alcohol lamp gives a flame which is too easily disturbed b y drafts a n d which is not easily regulated. Barthel a n d other lamps depending on t h e Bunsen principle are also not satisfactory when a
I THE
PATENT
EXPERT
AND
MANUFACTURER’
THE
By BERNHARD C. HESSE
By “Patent Expert” I do not mean that professional man who is called in by a litigant only a t the critical or crucial stage 1 Paper presented a t the 48th Annual Meeting of the American Chemical Society, Rochester, September 8-12, 1913.
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small flame is needed a t t h e early stages of t h e fusion. T o avoid these difficulties in determining sulfur in rubber, t h e writer some three or four years ago devised a simple and safe generator for gasoline gas, which is shown in t h e accompanying sketch. T h e large glass tube, 4.5 t o j.0 cm. in diameter, a n d 2 j cm. high, has fused into it t h e t u b e I for t h e admission of compressed air, which is carried down nearly t o t h e bottom through T. I t t h e n bubbles up through t h e layer of beads B. a n d passes out a t 0. surcharged with t h e vapors of petroleum ether or of gasoline, with which t h e large t u b e is filled u p t o t h e level G. From 0 t h e mixture of air a n d vapor passes through a black rubber t u b e t o t h e burner. The compressed air, a t a pressure of about one meter of water, is also led through black rubber tubing, which cannot cause contamination with sulfur. The object of t h e beads is t o break t h e stream of air up into innumerable small bubbles, without which i t would be impossible t o have a steady flame. Incidentally this causes more complete saturation with t h e gasoline vapor. The support S consists of a loosely fitting piece of brass tubing, soldered t o a brass plate, which is screwed down upon a block of wood. A couple of disks of thin sheet cork are placed a t t h e bottom of t h e brass t u b e t o lessen t h e danger of breaking t h e glass. A Tirrill burner, intended for ordinary gas, is used. T o prevent striking back i t is capped with a loosely fitting piece of brass tubing, about one centimeter long, across one end of which a piece of brass gauze is fastened with hard solder. T h e gauze should not be coarser t h a n 14-mesh, b u t if too fine some of t h e holes should be enlarged b y forcing through t h e m t h e sharpened t a n g of a file. A less satisfactory cap may be made by folding a piece of gauze over t h e end of t h e burner. The compressed air is turned on full a n d t h e burner is so regulated as t o give a non-luminous flame of t h e proper size. If t h e petroleum ether is too volatile, i t may be mixed with gasoline. If t h e latter alone is used, the mixture soon becomes too poor a n d i t is necessary t o set t h e t u b e in a large beaker filled with moderately warm water. One filling of t h e t u b e furnishes gas for several hours. After three or four years of almost constant use in this laboratory, t h e generator has proved entirely satisfactory and no accidents have occurred. T h e only precaution t h a t may be mentioned, a n d even this is hardly necessary, is t o extinguish t h e flame before turning off the supply of compressed air. BUREAU OF STANDARDS WASHINGTOX
ADDRESSES
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Yol. 5 , No.
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of a controversy long under way and most usually then in its final stages. On the contrary, I mean that professional man who is not only a highly trained and well equipped chemist, but who has also a natural or an acquired bent of mind which enables him to collect and assimilate the chemical and other facts relevant to the matter in issue, arrange them in logical
