116 JOURNAL OF THE [Octobcr, 



portion, with such tenacity that a stream of water, one-quarter of 

 an inch in diameter, from the city supply and at a pressure of 

 sixty pounds to the inch, even when directed against its side, 

 would fail to dislodge the curious creature. He has searched in 

 vain for any similar specimens upon fish taken from the same 

 pond." 



CLEANING DIATOMS FROM SAND. 



The Corresponding Secretary presented the following com- 

 munication upon this subject, also from Mr. Norman N. Mason: — 



" After removal of the organic matter with acid, by the usual 

 methods, add to the diatoms and sand in a large bottle thirty, 

 forty or fifty times the quantity, by measure, of water, and gently 

 shake until they are mixed. This water, with the diatoms and 

 sand kept suspended by an occasional shake, is slowly poured in 

 a small stream upon the upper end of a strip of clean glass, 

 three feet long by three inches wide and securely supported. 

 The upper end of the glass should be from one-eighth to one- 

 quarter of an inch higher than the lower end. and the glass 

 should be level transversely. Beneath the lower end place any 

 convenient receiver. The water and diatoms will pass into the 

 receiver. The sand, which will form little bars on the glass, 

 must be removed occasionally, as it gradually creeps towards 

 the lower end of the glass, and there would eventually pass into 

 the receiver. 



"The loss of diatoms will be very small. Usually one pour- 

 ing is sufficient for cleaning. The sand can be re-washed if 

 necessary, or a little clear water, run over the sand on the glass 

 strip, will carry forward almost the last diatom ; but this will 

 scarcely pay for the trouble. A short piece of glass will cause a 

 failure, and too great an incline will be found almost as bad." 



"Norman N. Mason, 



Providence, R. I." 



Meeting of June 7th, 1889. 



The President, Mr. Charles F. Cox, in the chair. 

 Nineteen persons present. 



Messrs. Charles Adams Coombs and J. Egmont Schermerhorn 

 were elected Resident Members of the Society. 



