64 



THE INDIA RUBBER WORLD 



(November 1, 1915. 



plied under pressure. This treatment causes the fabric to 

 vibrate, producing a movement of the threads vi^ith the effect 

 of assisting the penetration of the rubber solution into the 

 goods. 



CoLU)iD.\L Sui.FHLR.— Frencli patent No. 446,692; Lumiere. 

 Crystallized hyposulphite of soda, 125 parts, dissolved in 1,000 

 parts of water, is mi.xed with a solution of dextrine, 200 part.s, 

 in 1,000 parts of water. To 300 volumes of the mixed solution, 

 60 volumes of 22-degrec hydrochloric acid is added. The col- 

 loidal sulphur precipitated from the hyposulphite is separated 

 by filtration, dried and used promptly, for it depolymerizes 

 rapidly. 



PATENTED TREATMENT OF EUBBER. 



CoNCENTR.MED RuBBER Latex.— British patent No. 24,680 

 (1914); Samuel Mihie. A Scotch inventor proposes to con- 

 centrate rubber latex for delivery to manufacturers. The pur- 

 pose of this treatment is to obviate the tedious manipulations 

 and expensive plant required to secure dry rubber from the 

 latex by the usual methods. The evaporation is conducted 

 either at atmospheric pressure or in vacuum, and is not carried 

 to the point of coagulation. The concentrated latex, while hot, 

 is placed in suitable air-tight vessels for shipment. 



The latex, prior to, during or after evaporation may be 

 treated with any suitable preservative to prevent decay. It 

 may also be treated under pressure to destroy by suitable tem- 

 perature any germs which may induce decay, the resulting rubber 

 not being impaired by temperatures considerably over the boiling 

 point, at which all harmful germs would be destroyed. Thus treated 

 and packed, rubber latex may be kept for comparatively long 

 periods without deterioration and, when required, is in a form 

 suitable for immediate use for a great variety of manufacturing 

 purposes, with or without the addition of water. It can be mixed 

 with almost any material and applied in many ways. 



The concentrated latex may be further treated or dried to pro- 

 duce rubber in the usual form. 



Poi.vMERiZATiON OF BuTADiENE. — British patent No. 17,253 

 ( 1914) ; A. Heinemann. Isoprene, or a mixture of isoprene and 

 butadiene, is dissolved in an equal volume of acetone, and 

 sulphur dioxide is passed into the cooled solution for about 

 four and one-half hours, or until a white precipitate ceases to 

 form. The saturated solution is allowed to stand for four days. 

 The precipitate is then separated and washed with acetone. 

 When dry it has but little strength, but when molded for four 

 days under a pressure of 6,000 pounds per square inch, to expel 

 the oily substances, the product possesses great strength, and 

 has properties similar to gutta percha and balata. It can be 

 vulcanized by heat without further addition of sulphur, yielding 

 a soft product or one similar to hard rubber. 



Caoutcholx from Isoi'REXE. — United States patent No. 

 1,146,253;. A. Heinemann. A process for the production of 

 caoutchouc from isoprene, by first passing a substance composed 

 of oxygen through the isoprene while maintaining the latter at a 

 low temperature and then heating the product for a time suffi- 

 cient to effect polymerization. 



promises to revolutionize the design of delicate balances aiul their 

 method of manipulation. Direct readings in milligrams and tenths 

 are not only rendered possible by the device, Init the time required 

 to make a weigliing is considerably reduced. The iiuiovation is 



LABORATORY APPARATUS. 



IMPROVED ANALYTICAL BALANCE. 



AT the recent National Exposition of Chemical Industries in 

 New York, an improved direct reading analytical balance 

 was shown which is attaining deserved popularity among analysts, 

 who are prompt to appreciate its advantage over the ordinary 

 balance, which necessitates a rider for fine weighing. The im- 

 provement is the use of a small chain so arranged that any propor- 

 tion of its weight may be progressively added to or removed from 

 the beam of the balance and the amount of this weight read 

 directly. The use of this chain in lieu of fine weights and rider. 



due to the efforts of Christian Becker of New York, the well- 

 known manufacturer of analytic balances. 



To operate the new attachment a thumb screw at the side of 

 the balance is rotated. This controls the position of a sliding 

 block on a vertical graduated scale. The chain is suspended with 

 one end attached to the beam and the other to the sliding block. 

 Movement of this block adds more or less of the chain weight to 

 the beam till balance is obtained. Altering the chain weight can 

 take place while the beam is in motion and the weighing progress 

 without interruption or opening the window of the balance. Milli- 

 grams are read from the long scale and tenths of milligrams by 

 the vernier on the sliding block. The range of the chain weight is 

 considerable. In one of the popular-size balances the chain will 

 weigh from one-tenth milligram to 50 milligrams. By variation 

 in the chain weight the graduated scale can be calibrated for finer 

 or coarser weighing. The demand for the new balance is far in 

 excess of the facilities of the manufacturers to supply it and dem- 

 onstrates the prompt appreciation of the advantages offered by 

 the radical departure in design, [Eimer & ,\mend. New York.] 



RUBBER FILTER RINGS, 



Two new forms of rul)ber filter rings for use with filtering 

 crucibles are shown in the accompanying illustrations. One of 

 these is entirely of soft rublier and the other of hard rubber 

 with soft rubber flanges 

 ( shown in the cross sec- 

 tion). They are of spe- 

 cial value where the un- 

 obstructed use of the en- 

 tire sides and bottoms of 

 porous filters is desired, 

 as only about one-eighth 

 of an inch of the upper rim is grasped in the ring. The device 

 can be instantly applied or removed for cleaning and will fit any 

 60 degree funnel. It can be used with any filtering crucible on 

 the market. [E. H. Sargent & Co., Chicago.] 



