316 An Analysis of Plate-Glass. 



The source of the Dee, rising between Ben MacDhui on the 

 east and Braeriach on the west, is 4060 feet high, and most 

 probably it is the highest source in the United Kingdom. 

 The highest spring on Ben Nevis is only 3602 feet, accord- 

 ing to my barometrical measurements — that is, 766 feet be- 

 low the top of the hill ; another spring, on one of the highest 

 hills of the Grampians, Ben Aulder, reaches a height of 3650 

 feet. 



An Analysis of Plate-Glass. By Messrs J. E. Mayer and 

 J. S. Brazier. 



In going over the analyses of the diffei'ent varieties of 

 glass which have been recorded, we find that but little at- 

 tention has been paid to the composition of plate-glass, a 

 material which is almost becoming a necessary of life. It 

 is, moreover, remarkable that no analysis of the plate-glass 

 manufactured in Great Britain has ever been published. 



The following pages contain the results obtained from the 

 analyses of three diflFerent specimens of plate-glass, which 

 we undertook at the request of Dr Hofm^-nn.* These speci- 

 mens were procured at the three most extensive plate-glass 

 manufactories of England, which are, 



1. The British Plate-Glass Company, St Helens, Liver- 

 pool. 



2. The London Thames Plate-Glass Company, Bow Creek, 

 Black wall. 



3. The London and Manchester Plate-Glass Company, 

 Sutton, St Helens, Livei'pool. 



For the purpose of analysis, these specimens of glass were 

 reduced to the most minute state of division, which was 

 effected by levigating in the usual manner. None of the 



* I am indebted for these specimens to the kindness of Mr Fincham of the 

 British Plate-Glass Works.^Z>)- A. }V. Hofmann. 



