

BAIR-D &TATLOCK (LONDON) LTD. 



Apparatus manufactured of Pure, Transparent Silica, 

 for use at high temperatures. 



In addition to the ordinary forms of Laboratory Apparatus shown on following pages, 

 we can now supply in Quartz Glass special and complicated pieces to almost any 

 design. 



This apparatus is manufactured by a process which has the merit of producing articles of a symmetry hitherto 

 nattuined in silica ware. 



The apparatus being transparent, and consisting of pure silica in a thoroughly fused and homogeneous condi- 

 i)ii, fulfils purposes for which the ordinary opaque material is unsuitable. 



To those unacquainted with the properties of fused silica, the following may be of interest : 

 It does not crack on subjection to the most violent and sudden changes of temperature. 

 It is unattacked by the volatile acids, with the exception of hydrofluoric acid. 

 1 1 lias a melting point approximately equal to that of platinum. 

 It is harder than ordinary glass. 



Above i,oooC. it is permeable to hydrogen and certain other gases. 



Its co-efficient of expansion is .00000059 per degree Centigrade (about T V f that of platinum). 

 Its expansion, up to 1,000 C., is regular ; above 1,200 C. it contracts. 

 Its density is 2.2 (approximately). 



See pages 462-466 for prices. 



1CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS. 



461 



