•iOG Silk Manufacture. 



instantly make a signal, which on perceiving, all the boats return 

 immediately. A diver who trod upon a hammer oyster, and was 

 somewhat woundedf'thought he was bit by a shark ; consequent- 

 ly made the usual signal, which caused all the boats to return ; 

 for which mistake he was afterwards punished. The largest and 

 most perfect pearl taken last season, was about the size of a small 

 pistol bullet. ' 



CABINET CYCLOPAEDIA. 



SILK MANUFACTURE. 

 NO. X. 



Chemical, and Medical Properties of Silk. ' The color- 

 ing matter, which more or less tinges silk with a golden hue, 

 resides in the gum which the silkworm produces in such abund- 

 ance with the filament, and which exercises so important an 

 agency in facilitating all the preliminary processes of its manu- 

 facture. 



' If the cocoons be immersed in hot water a portion of this gum- 

 my or resinous substance will be dissolved, and will impart to 

 the water a light amber color. If alcohol be employed as the 

 solvent a much larger portion of this matter will be extracted from 

 the silk, and a tincture formed, which will retain its color even 

 after it has been exposed to the rays of the sun for a much longer 

 lime than would suffice to bleach the silk itself. 



' The knowledge of the fact that this coloring matter has a 

 greater affinity for alcohol than fc/r water led Mons. Baume to 

 adopt the following process for bleaching silk : — 



'A stone-ware vessel, of a nearly conical form, and capable of 

 holding about twelve gallons, was provided, having a large open- 

 ing at the top, and a smaller one, about an 'inch in diameter, at 

 the bottom. Vessels made of common pottery ware could not 

 be used for the puipose, as they would speedily have been ren- 

 dered unserviceable by the acid employed in the bleaching. From 

 the same cause, the stone ware even ])roved to be not very dura- 

 ble. All roughnesses on the inside surface of the vessel, which 

 could have broken the threads of silk, were carefully rubbed down 

 with pumice stone. The small aperture at bottom was closed by 

 a cork, tlnough the centre of which a glass tube, of a quarter of 

 an inch diameter, was passed, and, except at the time when it 



