•^82 Piroceedijigs of Societies. 



. 1. Boulton and Watt's single acting engine. Elevation, 



'-'• tlo. do. Section. 



3. Y Side and front views of the mechanism for opening and shutting 



4. / the valves. 



5. Pl?n of the beam, — general plan, and details, 

 t). Lloyd's steam engine, Elevation and FJan. 



Froin this brief notice, the reader will be able to form a pretty correct 

 notion of this valuable work, which promises to reflect great credit upon 

 Dr Birkbeck, and upon the respectable civil engineers by whom he is as- 

 sisted. 



Art. XXXVIIL— proceedings OF SOCIETIES. 



1. p7'oceedings of' the Royal Society of Edinburgh. 



March 19, 1827. — Professor Dunbar read an inquiry into the struc- 

 ture of the Greek, Latin, and Sanskrit verbs, with some observations to 

 show that tiie latter were derived from the former. 



April 2. — The following gentlemen were elected Members : 



The Reverend Edavard Burnet Ramsay, A. B. of St John's College, 

 Cambridge. 



The Reverend James Walker, D. D. of St John's College, Cambridge. 



Sir William Hamilton road an Essay " on Phrenology considered in 

 its constitution/' 



April 16. — There was read a Paper " on a New Combustible Gas, by 

 Thomas Thomson, M. D. Professor of Chemistry, Glasgow. 



This gas was obtained from pyroxylic spirit^ formed by the distillation 

 of wood, and manufactured by Messrs Turnbull and Kamsay of Glasgow. 

 Pyroxylic spirit has a specific gravity of 0.812, and an agreeable smell, and 

 is used in lamps in place of alcohol. Dr Thomson found that the gas ex- 

 tricated from a mixture of aqua regia and pyroxylic spirit consisted of 

 New inflammable gas, _ - - 29 



Nitrous gas, . - - - 63 



Azotic - - - - - 8 



100 

 the specific gravity being 1.945, that of air being 1. The specific gravi- 

 ty of the new gas was 4.1757, and it was composed as follows : 



i Atom hydrogen, - - - 0.128 



i Atom carbon, - - - - 0.750 



li Atom chlorine, - - - 6.750 



7.625 

 and its atomic weight is 7.625. Hence Dr Thomson calls it the Sesqui- 

 chloride of Car bo- hydrogen. 



On the same evening there was read another paper by Dr Thomson, en- 

 titled Some Experiments on Gold. The object of this paper was to deter- 

 mine whether the peroxide of gold contained two or three atoms of oxygen. 

 The evidence from the analysis of Berzelius and Javal was in favour of three 



