66 
Observations , fyc. 
[March, 
The very satisfactory results of the long series of experiments alluded to, are in 
a great measure owing to the zeal, intelligence and industry of Private (now Lance 
Corporal) James Menzies, of the 19th Company, who assisted me in the operative 
part, sometimes working alone, sometimes in the superintendence of other Pri- 
vates. 
Establishment for Field Instruction, 1 
1. The best natural water Cements of England are the Yorkshire Cement, the 
Sheppy Cement, and the Harwich Cement. 
As analyzed by Mr. Porrett, and other eminent chemists, these stones consist 
chiefly of carbonate of lime, silica and alumina, with a proportion of the oxides of 
iron and manganese, and of carbonate of magnesia. To analyze any mineral sub- 
stance accurately, so as to ascertain the precise quantities or proportions of all 
its component parts, requires more time than architects, engineers, or builders, in 
full employment, can usually spare ; but to judge whether any stone be a water 
cement or not, the following rough analysis will be perfectly satisfactory. 
2. Take any of the powerful acids, such as the muriatic or nitric acid, and pour 
a little into a wine glass, diluted with about an equal quantity of water, and into 
this drop a fragment of the stone. If it should not effervesce at all, there is no 
calcareous or magnesian matter in it, and therefore it cannot be a cement. If it 
should effervesce, and entirely dissolve, it is pure lime or magnesia, both of which 
are white. If it should effervesce, and partially dissolve, leaving a residue, it is pro- 
bably a water cement, or a water lime. 
3. The next test, and the most conclusive one, is to burn another fragment of 
the stone, in a Cornish crucible, with a cover, in a common fire, or simply in the 
fire itself, without a crucible, heating the specimen gradually, that it may not burst, 
and keeping it afterwards exposed to a full red heat for two or three hours. 
Take it out of the fire, and put a small fragment of it into a wine glass of diluted 
muriatic (or other) acid: if it should effervesce violently in the acid, it is imper- 
fectly burned. 
Chatham , 7 th of July, 1830. f 
§ 1 . — Of the Natural Water Cements of England. 
in the basin. 
