December 20, 1895.] 



SCIENCE. 



841 



were to establish courses of instruction, 

 similar to the best in Europe, for the train- 

 ing of experts in school sanitation and hy- 

 giene. Edward M. Haetwell. 

 Boston, Mass. 



A SI3IPLE APPARATUS FOB COLLECTING SAM- 

 PLES OF WATER AT VARIOUS DEPTHS. 

 Various devices have been used for col- 

 lecting samples of water for bacteriological 

 examination at different depths below the 

 surface of a pond, but few of them are sat- 

 isfactory. Some are too complicated and 

 liable to get out of order; some are too ex- 

 pensive; some are too fragile for transporta- 

 tion; some cannot be well sterilized; wliile 

 others have the besetting sin of operating at 

 the wrong time or of failing to operate 

 when required. Eealizing the great im- 

 portance of having a reliable method for 

 collecting samples, the writer, after much 

 experimenting, decided upon the form of 

 apparatus here described. 



At the upper end a strip of the lead is cut 

 out and turned downwards, as shown in the 

 figure, so as to form a rest for the bent arm 

 of the glass tube. The glass tube is held 

 in place either by a stopper pressed into 

 the top of the tube or by a suitable spring 

 clip passing around the bent arm and the 

 pi'ojecting strip of lead. The weight of the 

 lead is sufficient to sink the apparatus. A 

 bail at the top of the lead pipe is attached 

 to a spiral spring about eight inches long, 

 which in turn is fastened to the cord or 

 wire by which the apparatus is lowered. 

 To the upper end of the spring there is at- 

 tached a flexible wire, cai-rying at its lower 

 end a small brass tube, one inch long, 

 of such a diameter that it will easily fit 

 over the end of the bent arm of the glass 

 tube. The length of the flexible wire and 

 the stiffness of the spring are so adjusted 

 that when the apparatus is suspended by 

 the cord in the water the flexible wire is 

 slack ; but when a sudden jerk is given 



It consists primarily of a glass tube f 

 inch in diameter and 5 inches long, closed 

 at one end and having the other end drawn 

 out at right angles and bent downwards as 

 shown in the figure. The air is partially 

 exhausted by means of an aspirator and the 

 end of the tube sealed in the flame. 



This vacuum tube is essentially the same 

 as that first recommended by Pasteur, 

 though he obtained his vacuum in a differ- 

 ent way. 



After being sterilized the tube is jslaced 

 in the collecting frame, which consists of 

 a piece of lead pipe about seven inches long 

 and having an internal diameter of ^ inch. 



to the cord the spring stretches so much 

 that tension is brought on the flexible wire 

 and a sudden pull communicated to the 

 bent arm of the tube, resulting in the same 

 being fractured. If the bent arm has pre- 

 viously been scratched with a file the break 

 will be an even one. 



The operation of collecting a sample is 

 quite apparent. The glass tube being fas- 

 tened in its place and the brass cap being 

 put over the end of the bent arm, the ap- 

 paratus is lowered to the required depth, 

 care being taken that the cord runs out 

 smoothljf and without jerking. A sudden 

 jerk is then given to the cord. This breaks 



