1 78 The Commercial Products of the Sea. 



time. It is necessary before the bleaching to remove any 



calcareous matter which may adhere to the sponges, by 



soaking them for about an hour in dilute hydrochloric acid. 



The following is the chemical analysis of sponge : — 



Carbon 



If sponges were more generally abundant in commerce 

 and somewhat cheaper in price, many more uses might be 

 found for them. Thus, they would make excellent material 

 for stuffing beds and furniture — a use to which they have 

 already been put in America — for large and white tissues 

 for purifying and filtering liquids, paper stuff, etc. 



One of the uses to which sponge has of late years been 

 applied in America is to make what is termed elastic 

 sponge for stuffing in upholstery purposes. The raw 

 sponge is received in hard, dirty masses, filled with sand 

 and bits of shell. Being soaked in a large tank of 

 water, it expands into such condition that its quality 

 may be determined, and it is then sorted into two kinds — 

 the " soft " for mattress stock, and the " hard " for cushions. 



The cleansing process, which is an exceedingly impor- 

 tant one, then begins in another room. In order to effect 

 this, the sponge is first cut and washed, by passing for an 

 hour through a huge tube, in which there is a series of 

 knives, through which the sponge is made to pass by means 

 of the movement given to the water by a wheel. The 

 water, too, is constantly changing, so that by this process 

 the sponge is nicely cut, and its filth separated in part. It 



