Jl ME 1. 1915.] 



THE INDIA RUBBER WORLD 



495 



ing on the screen is then weighed. If difficult) is experienced in 

 getting the watet to run through the screen when beginnii 

 determination il is readily started by gently rubbing the under 

 side of tin screen with the lingers. \> regards size, a screen 

 <) inches in diameter lias been found very' convenient. 



By this test the manufacturer is enabled to pul a definite 

 numerical limit "it the quantity of coarse particles he will permit 

 in his raw materials. It also gives the pigment manufacturer a 

 means ol standardizing his manufacturing operations and oi 

 producing a uniform product. 



The tabulated results of the author's tests by this method, 

 conducted on commercial shipments of pigment, show wide varia- 

 tions m degree of fineness between lots of the same material 



supposed to he uniform. Among the materials represented, of 

 interest to rubber manufacturers, are iron oxide, graphite, as- 

 hestine. china clay, silica, whiting, Paris white, ultramarine, while 

 lead. Venetian red and "tilers employed in tile paint trade. 



\ modification of the above test, recommended in the case of 

 calcium and manganese oxides, consists in using in place of 

 water for washing, a basin of naphtha, placing the screen therein 

 so it will he covered to the depth of half an inch, brushing the 

 material through m the usual manner and finallj washing oft the 

 adhering particles from the hrush by means of a naphtha wash 



bottle. 



The amount of service that can lie expected from one of these 

 screens is limited where a high degree of accuracy is required, 

 especially where the pigments tested are strongly abrasive, such 

 as silica and iron oxides. After one hundred determinations the 

 screen should be tested against the master screen at frequent 

 intervals. A stock of standard pigments is maintained for com- 

 parison with shipments, using the same screen for test purposes. 

 For rapid testing of large shipments several standard screens are 

 employed on composite samples representing packages in unit 

 groups. 



The standard maximum limit for particles coarser than 350 

 mesh in pigments for p. mil manufacturers' use is 2.7 per cent. 

 Xo maximum limit of size is prescribed because of the further 

 reduction by grinding in the process of paint manufacture. 

 The figures shown in the tabulations presented by the authors 

 demonstrate that their standard is practically attainable and 

 might even be restricted to 1 per cent, without imposing undue 

 hardships on the pigment manufacturers. 



MINERS' ELECTRIC LAMP. 



The illustration shows a new miners' electric lamp that is said 

 to be safe, strong, light in weight, simple in design, efficient in 

 operation and of ample capacity. The outfit consists of a lead 

 plate I lattery connected by cable with 

 a lamp having a reflector. The 

 outfit complete weighs only 3'j 

 pounds, and only 4 ounces of 

 this weight is carried or 

 the cap. The battery is 

 non-spilling, and the 

 case is of medium 

 hard rubber. The 

 lamp hull), re- 

 flector a n d 

 t e r m i n a I 

 contact 

 block 

 are en- 

 cased in 

 a light 



drawn steel shell. A rubber gasket between the reflector and 

 the glass renders the case waterproof. The cable consists of 

 two braided strand rubber-covered conductors, each having a 

 steel piano wire at the center. These are twisted together ami 



then heavily rubber covered, to render the cable strong, well- 

 insulated and fur from kinks. [General Electric Co., Sche- 

 nectady, New York. I 



INTERNATIONAL TIRE STANDARDS AND THE S. A. E. 



At the meeting of Vpril 20 22, at Detroit, of the Society of 

 Automobile Engineers, the International Standards Division of 

 the Society placed particular emphasis on the necessity for edu- 

 cational literature to present to the attention of foreign intei 

 the advantages of international solid tire standards, and it was 

 agreed that the Institution of Automobib Engineers and the 

 >\ ..i Motor Manufacturers and I raders of England should 

 onsulted in this connection and their assistance obtained. 



This division of the S \. E. is composed of members resi- 

 dent in this country and abroad, and its object is the obviously 

 beneficial one of harmonizing dimensions of American and 

 Kuiopean solid and pneumatic tires and making such tires inter- 

 changeable throughout the world. The solid tire situation has 

 been selected for first attention. Standardization of the mount- 

 ing of solid tires ,,,, motor trucks has already been effected, and 

 I he society has re 'commended concentration upon three diam- 

 eters of tire only -32, 36 and 40-inch — as a means of reducing 

 inr cosl and to bring about the carrying of tires in stock at all 

 necessary places. The majority of the \merican truck manu- 

 facturers are now using tires of these three diameters ex- 

 clusively, in 3' 2, 4, 5 and 6-inch widths. 



A WESTERN OPINION ON FIRE HOSE. 



In an article on the subject of fire hose in the April quarterly 

 of the National lire Protection Association, lire Marshal 

 Harry YV. Bringhurst, of Seattle. Washington, says: "With 

 anything from a hand engine to a complete waterworks system. 

 a lire department should use for throwing water only the stand- 

 ard hose of 2^2-inch interior diameter. The saving in cost of 

 smaller sizes counts for little in comparison with the disadvan- 

 tages I nder conditions in which one pound of pressure is lost 

 by friction to each 100 feet of 2j4-inch hose, about three pounds 

 are lost in 2-inch and more than ten in lJ/^-inch." 



Continuing, he says that rubber, or "canvas" hose is more 

 expensive than cotton hose, heavier, less pliable and not so 

 strong, but that, on the other hand, there is no outside fabric 

 and nothing to dry after using, hence a double supply for each 

 hose cart is not needed. He states that first-class rubber hose 

 has lasted in volunteer fire departments longer than high-grade 

 cotton, with very little care, but that only the best quality can 

 give such results. Cotton hose, he claims, is strong, flexible and 

 the popular favorite, but the fabric must be carefully cleaned 

 and dried after using, so that an extra supply should always 

 be kept on hand to put on the cart or reels while this is being 

 done, lie says that there can hardly be too much care given 

 to cotton hose — that as soon as the lining gives way the hose 

 becomes weak at that point and worthless, and that the lining 

 itself is best kept cool and moist. 



In conclusion, he recommends the use of the specifications 

 approved by the Xational Board of Fire Underwriters, to hose 

 purchasers, as being reasonable and fair. 



MOTION PICTURES OF TESTS ON RUBBER COVERED WIRE. 



The Xational Fire Protection Association has recently pre- 

 pared a series of motion pictures illustrating the tests carried 

 on at the Underwriters' Laboratories in Chicago. These pic- 

 tures are available for use in educational work in connection 

 with accident prevention. The Laboratories' tests on rubber- 

 coated wire are very completely covered in these pictures, which 

 show engineers making the measurements prescribed in the Na- 

 tional Electrical Code, preparing samples for voltage breakdown 

 and wrapping tests, and such other features as can well be il- 

 lustrated. 



