158 CORRESPONDENCE. 



enough to see this process take place on two or three occasions 

 before, and once since, reading Mr. Hammond's paper. 



Judging from my own observations, I cannot see how, if a 

 little care was used, such differences of opinion could arise. 



Let me take this opportunity of thanking the P. M.S. for the 

 publication of a Journal, which I think is the best thing of the 

 kind I have yet seen. 



Yours, etc., 



Manchester. Fred. Farrow. 



To the Editor of " The loiirnal of the Postal Microscopical Society'^ 



Sir,— 



A friend tells me he has met with Bacillaria paradoxa in 

 the Canal, near Stoke, a few miles from this. Is not this unusual? 

 Is not the genus supposed to be marine, or at any rate a brackish- 

 water organism? 



Sto7ie, Staff. E. Bostock. 



Water Collecting-Apparatus. 



To the Editor of " The fourfial of the Postal Microscopical Society." 



Dear Sir, — 



I should be glad for you to publish in your Journal, if you 

 think it worth while, the following description of a piece of 

 apparatus, which I have found very useful in fishing for micro- 

 scopic objects in water. I have used it chiefly in searching for 

 Hydrachnidae, and so far have found no other piece of apparatus 

 so efficient for that purpose; it can, moreover, be easily manufac- 

 tured by anyone for his own use. 



Obtain a piece of thick brass wire, and at about 6 inches from 

 one end bend it into a ring 4 or 5 inches in diameter. After 

 connecting with some finer wire the two extremities of the ring, 

 bend the stout wire at right angles to the ring and continue it for 

 about 4 inches. Then make another ring about ih inches in 

 diameter, and there terminate the wire, — leaving the smaller ring, 

 however, not quite complete. The two rings will thus be parallel 

 to each other. On the upper ring stitch a piece of tape, and to 

 this sew a piece of muslin, made in the shape of a conical bag, 

 and having its wider end affixed to the tape. Into the lower 

 opening of this bag a small, wide-mouthed glass bottle, of about 

 two ounces capacity, should be fastened by a piece of thread or 

 fine string, and the lower ring is then sprung round the neck of 



