250 The Commercial Prodticts of the Sea. 



fishermen to open the sounds at once when taken from the 

 fish, and strip them of their cobweb, when they should 

 merely be rinsed with a little fresh water and dried in the 

 sun ; after which the longer they are kept exposed to dry 

 in the air, the better. 



Brazilian Isinglass. — One or other of the siluroid fishes 

 common in Guiana probably yields the Brazilian isinglass, 

 which comes chiefly in the form of lump or pipe. 



The fish which produce this article are caught annually 

 in great quantities at the mouth of the Amazon. The 

 isinglass is almost all sent to Great Britain. The fish 

 caught in the rivers are not of first-rate quality. Great 

 quantities of piracuru ( Vastris gigas), highly esteemed by 

 the natives, are taken on the Upper Amazon, and sent to 

 the Para market. 



A machorian, which gives 22 lbs. of salted or dried fish, 

 produces about i lb. oz. of isinglass. Thus, the weight 

 of the isinglass is to the fish as i to 20, a rule found to 

 be pretty general. According to the estimated take of fish, 

 the yield of isinglass should be 123,480 lbs. 



Supposing the price of isinglass to be but 2s. 6d. the 

 pound (at Para it is 4^. and sometimes 5^-.), and the price 

 of salt fish a penny per pound, we have the following as the 

 produce of the local fishery : — 



Isinglass, 123,480 lbs. at 2^. 6^. ... ^15,435 



Salt fish, 2,346,120 lbs., oXid. ... 9,801 



^^25,236 



From 750 to 880 cwt. of isinglass are shipped from 

 Brazil annually, of the value of 15,000 to ;^i6,ooo. 



In the Cape Colony som.e of the wine merchants make 

 use of the dried bladder of the kabeljauw {Scicena hololepi- 

 dota, Cuv. and Val.) instead of isinglass. 



