December i, 1906.] 



THE INDIA RUBBER WORLD 



76 



does not appear in the list. But since their general charac- 

 teristics are the same, we have reproduced (on the preceding 

 page) from Dr. Spire's book an illustration of E. ivsra, 

 showing the leaf formation, flower, and elongated seed pod.s. 

 The export of rubber from ludo-China has reached in a 

 single year 339 tons, most or all of which is the product of 

 vines, including the species here named. It is of no little 

 interest to learn that similar rubber plants exist in Formosa. 



THH RHSIN CONTENT OF INDIA-RUBBER. 



TH.VT the percentage of resin contained in a particular 

 kind of crude rubber does not always serve as a cor- 

 rect criterion by which to judge its commercial value is 

 asserted by Lj-man M. Bourne, of the Eastern Rubber Co., 

 New York. At the same time, when two samples of the 

 same kind of rubber show a different resin content, the sam- 

 ple containing the lesser amount of resin will give the 

 stronger and more elastic vulcanized compound. On this 

 account, says Mr. Bourne, it must be of inteiest to know- 

 that the resin content of nearly every kind of India-rubber 

 has increased during the past two or three years. 



Mr. Bourne has prepared a table of analyses, repeated 

 below, which show such increase, when compared with pre- 

 viously published results. The method employed was as 

 follows : Two or three grams of the sample were weighed 

 out, cut into small pieces, and dissolved in ben/ol. From 

 this .solution the rubber was precipitated b\' ethyl alcohol. 

 The mixture of benzol and alcohol was then decanted as 

 closely as possible through a silk filter and the precipitated 

 rubber washed several times with alcohol. The benzol alco- 

 hol mixture, carrying the resin in solution, was evajjorated 

 to dryness in a weighed flask on a water bath and dried, as 

 was also the precipitated rubber in vacuum at So° C. for two 

 hours. 



Mr. Bourne's table follows : 



(Irades. No. lots Percent. Percent. Approx. 



analyzed. Rubber. Resin. Shrinkage. 



.■\ddah niggers, Congo J 93.3 6.7 40 



Aruwinii, Congo 2 gi.l S.9 6 



Assam prime, India 6 84 2 15. S 25 



Assare, Urazil I 91. 1 89 



Beiiguela, Benguela 2 887 u.3 25 



Horneo, ist, Borneo I 88. 2 11. 8 38 



Borneo, 2nd, Borneo 2 80.7 19.3 45 



Borneo, 3rd, Borneo I 79.3 20.7 30 



Brazilianstrips.Bra7.il I 720 2S o 20 



Cameroon, Africa I 87.5 127 20 



Caucho ball, Brazil 24 90.0 10.0 33 



Caucho sheet, Brazil 14 91.0 9.0 38 



Caucho slab, Brazil 13 S6.S 132 33 



Conakry, West Africa. ... 1 93.3 6.7 15 



Coii,s;o, lower Conjjo 2 87.3 12.9 40 



Con.go, upper Congo 7 S6.3 13.S 16 



Congo, French Congo. .... . 2 90.5 9.5 33 



Congo, black, Congo 1 84 4 156 



Congo, Wainba, Congo 1 84.4 15 6 60 



Costa Rica, Costa Rica j S7.0 13.0 17 



ICquateur, ist, Congo 1 ((2.9 S. 1 



Ecuador strip, I'Xuador i 90.4 9.7 20 



(iaboon lump. West Africa. . i 27.6 724 ,>5 



Gambia, ist. Senejjainbia. . .. i 88.8 11.2 42 



Cold Coast lump. Africa 5 72.7 27.4 35 



Guayatjuil strip. Ecuador.... 7 89 8 102 2° 



Kassai, black. Congo stale., i 88.4 116 10 



Kassai, red, Congo 2 88.9 ii.o 30 



Kassai. red, 2nd, Congo .... i 94.6 5.4 



Kassai. red, 3rd, Congo . . . i S9.0 10 9 25 



Lahou twists, Congo i 9 .6 8.4 27 



Lagos lump, Lagos i 93.3 69 40 



Lopoii, ist Congo i 92.6 7.4 10 



Lopori, 2nd Congo 2 62.1 87.9 20 



Gradks. No. lots 



analyzed. 



Madagascar i 



Manicoba sheet, Brazil i 



Manga beira, Brazil i 



Massai, red, Congo 2 



Mas-sai, pink, Congo i 



Mexican, Caslilloa i 



Mexican Guayule 3 



Mongala, Congo 2 



Mozainbi<|ue i 



Niger paste, Africa i 



Para, fine, Brazil 23 



Para. Ceylon, fine 3 



I'ara, medium, Brazil g 



Penang Malaya I 



Penang, white, Malaj-a i 



Penanjj. prime, red i 



Penang, white i 



Peruvian tails 2 



Pontianak, Borneo 7 



Shebbro, West .\frica 2 



Shebbro. Conakry, W. .Africa I 



Twists, prime. West .Africa. . i 



Twists. 1st. West .Africa i 



Twists, 2nd, West Africa. . . . i 



Tuno gum i 



Uele, Congo 2 



West India slab i 



EUREKA -NON CROSS" THREAD COUPLINGS. 



THE couplings used with fire hose are hardly of less im- 

 portance than the hose itself. In this connection may 

 be mentioned the " non cross " thread with which the hose 

 made by the Eureka Fire Hose Co. (New York) is equipped — 

 a feature that is receiving much attention. All Eureka 

 couplings are made of bronze, and unless otherwise desired, 

 all the threads are of the non cross variety ; that is, they are 

 cut ofl" at the outer end to facilitate coupling and to prevent 



the possibility of the threads being crossed when the hose 

 connection is being made. These couplings are made with 

 threaded swivels, which consist of four annular threads, cut 

 male and female, in the inner and outer parts of swivel re- 

 spectively. These threads are standard 60 degrees and of 

 full depth and give a greater wearing surface than the ordin- 

 ary flanged lip swivel joint, while their V shape prohibits 

 any possibility of jamming, as the tendency of the joint is 

 to free itself. The threads, swivel, washer recess, and water- 

 way of the Eureka couplings are made at one setting of the 

 part in a lathe, and are consequently perfectly true to each 

 other. Adequate expansion pressure may be applied with- 

 out the slightest injury, and thej- maj' be attached with an 

 ordinary expander without the use of any special appliances 

 such as many other couplings require. 



The growth of the use of motor 'buses in England is 

 greatly stimulating the manufacture of solid rubber tires. 

 The Dunlop companj- are now making a specialty of tires of 

 this class. 



