138 



PRACTICAL MICROSCOPY. 



stern of a steamer. The sediment left in the bottom of 

 pails, barrels, and other vessels contains a good supply. To 

 obtain varieties not found at home, open a correspon- 

 dence with gatherers in other localities, who will gladly 

 exchange. 



Dr. Redmayne, in a short communication to 'Science- 

 Gossip' in 1875, described the simple arrangement for 

 diatom collection shown in Fig. 122. 



FIG. 122. 



A cork must be provided which fits the collecting bottle 

 tightly ; this is to be bored with two holes : in each is fitted 

 a glass tube as shown in the figure, one having a slight 

 curve a, the other b bent at right angles an inch from 

 the end. To the tube b is attached a piece of indiarubber 

 tubing about the length of the collecting-stick, and the free 

 end c may be held in the hand or fastened to the stick 

 with a small elastic band. 



To use the apparatus, the thumb of the right-hand must 



