replace the barium chloride solution when flowing out. The tube a t the dropping point then has the crosssection shown at c. I think t h a t i t is unnecessary, especially when the solution contains only moderate amounts of sulfate, to stir during precipitation when using this dropper, as, the two solutions being a t about the same temperature, the boiling continues vigorously, and further agitation is not required. The precipitation of barium sulfate in this manner requires no attention after the solution is set on the hot plate except t o tip up the tube and t o set aside t o digest later, and one man can carry on a number of precipitations a t one time. I n the determination of sulfur trioxide in cement in a limited time I obtain the best results under the following constant conditions: wt. cement, z grams :
hot water added, 30 cc:. ; conc. HC1 added, 8 cc. (making about 3 cc. free acid in final solution or about 0 . j per cent. acidity) ; boiling I minute, filtering, washing twice ; precipitating volume, 2 5 0 cc. ; volume BaCl, solution, I O cc. I O per cent. ; time adding BaC1, solution, about z minutes; time boiling after adding BaCl, solution, j minutes; time digesting. I hour; filtering; washing 5 times. 4 series of fifty determinations of sulfur trioxide in cement made recently by this method gave the following results : Gram iiverage weight T(aS04 for series.. . . . . . . . . 0.091s Weight BaS04 from composite (1). . . . . . . . . . . . . . 0.0918 Weight BaSOl from composite ( 2 ' ) .. . . . . . . . 0.0923
Per cent. SOs 1.575 1.575 1.58
Although small amounts of barium sulfate can bc recovered after several hours' standing from filtrate5 obtained after one hour digestion on hot plate, still results by the above method have always been found to be consistent, and to wait twelve hours or so in order t o add a possible one-hundredth of one per cent to a result seems unnecessary in technical work. If the above method were universally used there mould probably be much closer agreement in the results o f different analysts. especially in the cement industry. THE TEXAS PORTLAND CEMEST C o CEVIENT.TEXAS
AN ADAPTED WILEY EXTRACTOR FOR RUBBER EXTRACTIONS R y CHARLES P.
The ordinary Soxhlet extractor is too small f u r acetone extractions when large quantities of rubbw are desired. The Proctor extractor used in tannin extractions is also not satisfactory for rubber work. For charges up to 2 j o grams, a modified or adapted Wiley extractor has been used for several years and has given satisfactory results. This apparatus consists of the well-known Wiley metallic condenser, b u t in place of the original reservoir, a large ( 2 inches in diameter), long (IS inches), a.nd strong glass tube with ground thick lipped top is substituted. The uniform diameter of the tube permits of large charges of thin sheeted rubber carefully rolled upon fabric being inserted into the tube, suspended from the condenser within range of the drip of the condensed and falling solvent. To prevent a contamination of the purified rubber by accidental splashing of the resin solution, a disk of filter paper or cotton is inserted between the hanging charge and the solvent reservoir. A metal spiral made of sheet tin is useful in prcvcnting a superheating of the solvent and consequent foaming. A steam bath may be utilized in furnishing the rcquired heat for acetonic and alcoholic extractions. Higher temperatures for nitrobenzene or kerosene work are obtained by direct flame carefully regulated. or by a paraffine bath. 395 DOYLESTREET AKRON,OHIO
ADDRESSES COMMENTS ON THE REPORT OF THE INVESTIGATION O F THE UNITED STATES PATENT OFFICE' BY L. H . BAEKELAND Received April 18, 1913
Whoever is interested in the patent situation of this country. should make it his duty to read the unusually interesting publication just issued by the U. S. Government, which covers 624 closely printed pages. On August z I , 19 I 2 , the following joint resolution was passed: "That the President of the United States be, and he is hereby, I Sixty-second Congress. 3 d Session, House of Representatives, Document S o . 1110. Report of the Investigation of the United S t a t e s P a t e n t Office. made by the President's Commission on Economy and Efficiency, TI-ashington, December 9 , 1 9 1 2 .
Fl>X
Received March 2 2 . 1913
II
requested to cause the accountants and experts from official and private life now or hereafter employed in the inquiry into meth ods of transacting the public business of the Government in the several executive departments and other executive Government establishments, known as the Commission on Economy and Efficiency, to investigate fully and carefully the administration of the Patent Office with a view of determining whether or not the present methods, personnel equipment, and building of said office are adequate for the performance of its functions taking into consideration the present character and volume o l business, and also such increase in complexity or volume as may reasonably be expected in the future, and to ascertain and recommend specifically to Congress not later than December I O ,
