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On the Disintegration op Diatomaceous Deposits. 



By M. Guinarp, Corresponding Member of the Belgian 



Microscopical Society. 



Translated from the u Bulletin de la Societe Beige de Microscopic" 



Many means of disintegrating the fossil diatomaceous deposits 

 are known. Amongst others, one has been lately indicated by M. 

 J. Brim. The plan recommended by the learned Genevese Pro- 

 fessor is based upon the recrystallization of sulphate of soda, but 

 the operations necessary for obtaining complete success are too 

 delicate, and exact many precautions difficult to realize practically, 

 the most essential, to obtain saturation with sulphate of soda, being 

 the heating of the water to about 33° C, and the consequent use 

 of the thermometer in the vessel serving as a water bath. 



I would point out a salt which I believe has not yet been sug- 

 gested for this operation, and which by reason of its easy manipu- 

 lation may be of use for the disintegration of diatomaceous deposits. 



This method consists in introducing some fragments of the 

 deposit into a tube, covering them to the depth of about two centi- 

 metres with crystals of common commercial acetate of soda (not 

 pure), and finally adding thereto one or two drops of water. (For 

 operating on a larger scale the proportion of water is five cubic 

 centimetres to 100 of the salt.) The tube is then plunged into a 

 water bath, and when the water is near the boiling point the salt 

 will dissolve. The deposit absorbs the solution of acetate of soda 

 and is left in the hot water for about ten minutes, the tube then is 

 withdrawn from the bath, and the solution allowed to cool, or if it 

 is desired to quicken the action, the tube may be plunged into a 

 vessel of cold water. A minute crystal of acetate of soda is then 

 dropped into the solution, which owing to this supersaturation will 

 suddenly crystallize. This operation may be repeated two or three 

 times with the same solution, and it is rarely that the deposit will 

 not be perfectly reduced to powder. 



By these means I have procured the disintegration of the most 

 refractory deposits, such as those from the Isle of Fur, in Jutland, 



