Mr. Bowman on Tribasic Boracic Mther. 547 



had succeeded in obtaining specimens of hydrated silicic acid 

 perfectly hard and transparent. 



This was the first time silica had been obtained artificially 

 in a state at all resembling quartz ; and though it is anything 

 but probable that nature ever manufactured her rock-crystal 

 or hydrophane by the action of moist air on silicic aether, I 

 felt interested in the subject, and prepared a quantity of the 

 aether according to Ebelmen's directions, viz. by mixing to- 

 gether liquid chloride of silicon and absolute alcohol. I then 

 placed a little of the aether in some test-tubes, closed them 

 with corks having a small slit cut down the sides, to allow the 

 access of air, and put them, with a small pan of water, under 

 a bell-glass. 



In the course of a couple of months a thin ring of trans- 

 parent silica was deposited round the inside of the tubes, an 

 inch or two from the surface of the aether, apparently at the 

 point where the aethereal vapour had come in contact with 

 the moist air. This silica, though hard, is extremely brittle, 

 and will scarcely bear j-emoval from the glass on which it is 

 deposited without injury. It appears destitute of crystalline 

 structure, and is wholly without action on polarized light. 



It occurred to me as highly probable, from the analogous 

 properties of silicon and boron, that if chloride of boron were 

 carried into absolute alcohol, a boracic aether would be pro- 

 duced by a decomposition similar to that of the chloride of 

 silicon. 



I passed pure and perfectly dry chlorine over an ignited 

 mixture of charcoal and boracic acid, and purified the gas 

 thus formed from the free chlorine with which it was mixed, 

 by passing it through two U-shaped tubes filled with copper 

 turnings. To the last of these I connected two of Liebig's 

 bulb-apparatus charged with absolute alcohol. 



As soon as the gas began to fill the first bulb, a heavy li- 

 quid was deposited above the surface of the alcohol, through 

 which it sank and gradually mixed, forming a clear solution. 

 The temperature of the liquid rose considerably during the 

 formation of this heavy fluid, and to prevent it getting too 

 hot I immersed the bulbs in cold water. 



After some time the liquid in the bulbs became turbid, 

 owing to the formation of minute globules of a new fluid im- 

 miscible with the first ; this gradually increased considerably 

 in quantity, and at length occupied nearly as much space as 

 the other. This new fluid was considerably lighter than the 

 first, and the globules as they separated rose to the surface, 

 forming a distinct layer, similar to oil floating on the surface 

 of water. 



During the formation of this second fluid the temperature 



