198 ANNUAL OF SCIENTIFIC DISCOVERY. 



of sulphur, say from five to seven per cent, by weight of the quantity 

 of rubber used, will readily vulcanize, upon exposure to a heated atmos- 

 phere, say 260 Fah. The quantity of potash may be increased the 

 exact amount is immaterial ; but the best elasticity. I obtain is, by the 

 use of two ounces to sixteen of rubber. This preparation may be spread 

 upon textile fabrics, fine figured or colored, and exposed to a heated at- 

 mosphere, without in the least discoloring or causing the loss of color 

 to the fabric. It is free from offensive sulphur smell, and will not be 

 aflected by atmospheric changes. For making my fabric harder and 

 with less elasticity, as also for purposes of cheapness, I combine whit- 

 ing, lamp-black, and such other articles as are well known to give body 

 and firmness to the rubber. These may be incorporated in the rubber 

 and potash compound, by the usual methods, well known to manufac- 

 turers. Appleton's Magazine. 



OIL FOR LUBRICATING MACHINERY. 



M. BOUDET describes an oil, which the French call Hard, used for 

 greasing machinery. It is made by adding one part of caoutchouc, cut 

 into small pieces, to fifty parts of rape oil, and applying heat until the 

 caoutchouc is nearly all dissolved. This oil is more unctuous than most 

 of the oils used for machinery, and is not so much affected by the rapid 

 motion of the parts to which it is applied, or by other influences to 

 which it may be exposed. It remains fluid at temperatures below the 

 freezing-point of water, and offers little obstruction to the commence- 

 ment of motion in the machines. M. Boudet suggests the following 

 method of determining the proportion of caoutchouc contained in this 

 kind of oil : A weighed quantity of the oil is saponified with potassa, 

 and the dry soap treated with spirit, which dissolves the soap with the 

 aid of heat, and leaves the caoutchouc. The insoluble residue is 

 washed with water containing a sixth part of spirit. 



INFLUENCE OF OIL ON WATER. 



PROF. HORSFORD, at the Albany meeting of the American Associa- 

 tion, read a paper, entitled, " On the occurrence of placid water in the 

 midst of large areas where waves were constantly breaking." 



The Professor said he had noticed frequently that there were 

 spaces of some extent, in places where the waves broke, which were 

 very smooth ; that though the swell, or rise and fall, of the water was 

 just as great, yet there was no breaking of the waves, no white crest or 

 comb ; that he believed that these smooth spots were occasioned by 

 oil or oleaginous matter, which had accidentally happened to be spread 

 on the surface at such places. To test this, he had, himself, when 

 there was quite a stiff breeze, with waves on the surface of the water, 

 which broke with considerable of a comb or crest, emptied a vial of oil 

 on the water from a boat. The effect WAS instantly seen. As far as 

 the oil spread the water was smooth, and the waves did not break ; 

 and, what was very curious, the oil spread over the surface almost as 

 rapidly to windward as it did to leeward. He had, therefore, inclined 



