8 



BULLETIN 819, IT. S. DEPARTMENT OF AGRICULTURE. 



the body of the tube ; the whole tube is then heated to drive out the 

 air and sealed, forming a partial vacuum tube. The body of the 

 tube is held in the clasps on the apparatus, and the capillary 

 point passes through the slit and extends out in back. When ready 

 to take a sample of deep water, the tube is placed in the clasps as 

 described, and the apparatus, suspended from a strong cord, 

 is lowered to the required depth. A heavy lead weight, which is 

 pierced so that it will slide over the cord, is held in the hand until 

 the apparatus is at the necessary depth. The weight is then al- 

 lowed to slide down the cord. When it reaches the apparatus it 

 strikes the sliding knife edge hard enough to cause the edge to slide 

 down, breaking the capillary point of the tube. The tube will then 

 fill up with water to about two-thirds of its capacity, and may be 

 lifted up without any further water being taken in. In this man- 

 ner a sample of from 15 to 25 cc. can be secured from any depth. 

 Samples thus obtained were carried in a specially constructed rack 

 to the laboratory. The tops of the tubes were then broken, pre- 

 cautions being taken to avoid contamination, and the samples were 

 analyzed in the same manner as surface water samples. 



Table 3. — Analyses of surface and deep tcater samples. 







Samples. 



Result. 



Date. 



Bed No. 



Samples. 



Result. 



Date. JBedNo. 



Location. 



Num- 

 ber. 



Posi- 

 tive. 



Nega- 

 tive. 



Location. 



Num- 

 ber. 



Posi- 

 tive. 



Nega- 

 tive. 



1917. 

 Mar. 26 



Apr. 4 



Apr. 12 



Apr. 26 



Do.. 



May 22 



May 24 



May 29 



May 31 



June 4 



June 8 



June 12 



6 



6 



6 



7 



5 



4 



6 



3 



6 



6 



6 



6 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



iDeep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



4 

 9 

 3 



12 

 3 



12 

 2 



10 

 1 

 2 

 3 



11 

 3 

 8 

 3 

 8 

 3 

 6 

 3 

 8 

 3 

 8 

 2 

 6 





 

 

 

 

 

 

 

 

 

 

 

 

 

 1 

 1 

 

 2 

 

 

 

 

 

 



4 

 9 

 3 



12 

 3 



12 

 2 



10 

 1 

 2 

 3 



'I 



8 

 2 

 7 

 3 

 4 

 3 

 8 

 3 

 8 

 2 

 6 



1917. 

 June 14 



June 21 



June 26 



June 28 



July 3 



July 5 



July 9 



July 11 



July 16 



July 19 



July 24 



July 21 



2 



6 



4 



4 



1 



5 



2 



2 



6 



3 



2 



2 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep . 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



IDeep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



/Surface 



\Deep 



3 

 8 

 3 

 8 

 3 

 8 

 3 

 8 

 3 

 7 

 3 

 8 

 3 

 8 

 2 

 8 

 4 

 8 

 4 

 7 

 4 

 8 

 3 

 8 





 1 

 

 

 

 

 

 

 

 



1 



3 

 

 

 

 

 

 

 

 

 



§ 







3 



3 

 8 

 3 

 8 

 3 

 8 

 3 

 7 

 2 

 5 

 3 

 8 

 2 

 8 

 4 

 8 

 4 

 7 

 4 

 8 

 3 

 8 



Results. 



The analyses of water samples give a much smaller number of 

 positive results than do analyses of the oysters or swabbings. from 

 the oyster house. But 2 positive samples of surface water have 

 been found in the 71 samples examined, or 2.8 per cent, and but 7 



