208 TlMEHRI. 
" most gratifying to me, as I had received adverse opinions from 
" other experienced persons. This happened I think in 1862 : from 
"' that time to the present I have been engaged in investigations how to 
" produce the material cheaply and how to dry or coagulate it rapidly. 
" In both particulars I believe I have succeeded so far as to warrant the 
" importation of steam machinery to be applied to its extraction ; and 
" by a fortunate action I have discovered how to dry or coagulate it, 
" preserving the characteristics of elasticity, at a single operation, by 
" the addition of a single ingredient not very costly." As a sequel to, 
and comment on, this I quote the following passage from the preface to 
the Catalogue of the British Guiana Exhibits sent to the Paris Universal 
Exhibition of 1876, page 69: — "To prevent the waste, and at the 
" same time secure the large and continuous supply of balata which 
" they were anxious and urgent to procure, the promoters of the enter- 
" prise in England incurred heavy expenses in adopting and sending 
" out machinery for extracting the juice from the bark, and a mill 
" driven by steam power was erected and worked both in Mahaicony 
" Creek and Berbice ; but after large shipments of the gum thus pro- 
" duced had gone forward, it was only a short while ago pronounced to 
" be almost unmerchantable from the excessive amount of impurities it 
" contained ; at the same time, owing to a decline in the price of gutta- 
" percha, a check was given to all balata operations." 
" I have not been able to ascertain definitely what was the substance 
used by Sir William Holmes to coagulate the milk but presume it to 
have been alum. I have tried the action of alum, and also of its 
cheaper substitute, sulphate of aluminum, on the milk, but was not at all 
satisfied with the results. High wines, 40 over proof added to the milk 
in the proportion of about an equal bulk coagulate it completely, but 
the product after washing and drying, although perfectly white, is hard 
and comparatively inelastic." 
Whatever the substance was, alluded to by Sir William 
HOLMES for coagulating the balata milk, of which he 
speaks so confidently in his communication to the 
Society of Arts, the balata thus made would appear to 
have been received, like that made by his machinery, 
unfavourably in the market, for the system was not long 
practised. 
