520 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



frequent changes of the water and removal of all fatty and 

 bloody particles. The warmer the water, the more rapidly 

 the operation is completed. The bladders are finally re- 

 moved, and cut longitudinally into sheets, which are exposed 

 to the sun and air, being laid out to dry, with the outer face 

 turned down, upon boards of linden or bass-wood. 



The inner face is pure isinglass, which, when well dried, 

 can with care be removed from the external lamella*. The 

 finer sheets thus obtained are to be placed between cloths 

 to keep them from flies, and are then subjected to a heavy 

 pressure, so as to flatten them out and render them uniform. 

 After this they are assorted and tied up in packets. The 

 packets composed of the isinglass of the large sturgeon usu- 

 ally contain from ten to fifteen sheets, and weigh a pound and 

 a quarter ; those of the others contain twenty-five sheets, 

 weighing a pound. Eighty of these packages are usually 

 sewed up in a cloth bag, or sometimes inclosed in sheet-lead. 



The outer lamellas of the air-bladder, after the isinglass 

 proper has been removed, also contain a considerable quanti- 

 ty of glue, which, when softened in water, is scraped off* with 

 a knife and moulded into little tablets of about the size of 

 a silver dollar, and then dried. This form of isinglass is 

 packed in boxes, and is less expensive than the other. 



It is said that an excellent isinglass has been made from 

 the scales of shad and herring, which are first freed from their 

 silvery coating. This may furnish a useful hint to persons 

 who are near some of the great fishery establishments of the 

 country; that at Alexandria, Virginia, for instance, where 

 hundreds of thousands of shad are scaled and salted every 

 year. Fisheries of the Arctic Seas, Schultz, 1873, 67 



DIFFUSION PROCESS IN MAKING SUGAR. 



The diffusion process, which of late years has been exten- 

 sively employed in Europe for the extraction of sugar from 

 beet-root, has been subjected to very thorough tests in man- 

 ufacturing sugar from the cane. The process has for some 

 three years been in operation at the works of the Aska Com- 

 pany, Madras Presidency, East India, and has given admira- 

 ble results. It yields, without much added difficulty, or 

 much greater expense than the older processes, about 95.4 

 per cent, of the sugar present in the cane, thus increasing the 



