Note on the Collection of Sediments. 471 



The apparatus consists of a tube about 60 ctm. long and 

 10 ctm, in diameter. The tube is cylindrical for about 

 three fourths of the length, for its remainder the sides 

 gradually convei'ge until the lower opening is less than 5 

 ctm. in diameter. On this smaller end is carefully ground 

 a glass cap which is conical internally, and externally has 

 a flat bottom to enable it to stand like a cup. 



In addition to the tube and cap there is a glass rod firmly 

 inbedded at one end in a rubber stopper (c) that exactly fits 

 the lower opening of the tube from the inside. 



The tube will hold about 3 litres but is graduated to con- 

 tain 1 and 2 litres in case of a limited supply or a very 

 heavy sediment. 



To use the apparatus the cap is carefully adjusted, the 

 samples thoroughly shaken and the tube filled to the con- 

 taining mark. It is then covered and suspended quite per- 

 pendicularly in the rings of a large Bunsen stand. If the 

 tube be properly constructed all but a mere trace of sediment 

 will have gathered into the cup at the bottom within a few 

 hours. It has been my custom to examine these tubes at 

 the end of four or five hours, and if there is any visible deposit 

 on the sides to give a gentle rotatory motion to the water 

 and again leave them undisturbed for several hours when, 

 as a rule, not a trace of sedimentary matter will be found 

 out of the cup at the bottom. 



To obtain the sediment the stopper is introduced quietly 

 from above by means of the rod, and the cup is at once de- 

 tached without losing any water or disturbing the sediment. 



There is thus obtained the sediment of three litres of water 

 in about 50 cubic centimeters ready for microscopic exam- 

 ination or quantitative estimation. By means of a tared 

 filter the sediment can be filtered off, dried and weighed in 

 a few hours. 



Note. — Some time after this apparatus was shown at the 

 Natural History Society, my attention was called at Ottawa 

 to a tube of similar design invented by Dr. Wynter Blyth, 

 and figured by him in his Hand-book on Foods. Dr. Blyth's 

 tube is quite small, and the slope very much greater, the 



