156 Canadian Record of Science. 



joints) the nozzles C, as shewn enlarged ;n the lower 

 figure. D is a strip of bent copper to serve as a gauge. 

 The vertical distance between the points E and F is 2J 

 inches. 



In the instrument diagramed in the figure, I have tried to 

 overcome the objectionable features of the Redwood con- 

 struction. The copper vessel first used by me is re- 

 placed by a brass vessel cast in one piece and shaped on 

 the lathe; its walls are one-quarter of an inch thick, and 

 its other dimensions as formerly. The large size of the 

 cup enables it to contain 1,200 cc. of oil at the beginning 

 of each test. The small portion (50 cc.) withdrawn flows 

 at a practically uniform rate throughout the time that 

 the experiment lasts, since the large horizontal area of 

 the vessel makes the variation of rate due to gravity to be 

 insignificant. The oil is withdrawn from the middle of 

 the whole quantity contained in the vessel, and although 

 the outer layers of oil may slightly change their tempera- 

 ture, the middle portion is sensibly constant during the 

 time of the test. The tubulure (I used at first the agate 

 tube from the JRedwood instrument, but now it is replaced 

 by nozzles of phosphor bronze bored to y 1 ^, \ and f inch 

 respectively) is not placed at the bottom of the vessel ; 

 consequently particles of dust, sand, etc., which may be acci- 

 dentally present, do not interfere with the working. 

 Finally, the shape of the conical tube carrying the agate 

 makes it very convenient to insert the necessary flask, 

 whose neck fitting somewhat closely into the hollow cone 

 prevents the cooling effect of air currents upon the mouth- 

 piece, a very important consideration, since they constitute 

 an unascertainable and, no doubt, a varying factor in the 

 results obtained with other instruments. I employ a ring 

 burner in heating the oil, and a wooden spatula for stir- 

 ring it. It is convenient to use two flasks, so that one 

 may be draining while the other is in use. In this way a 

 very large number of experiments may be made, even at 

 high temperatures, in a short time. The inexpensive char- 

 acter of the apparatus is in contrast with the complicated 



