October i8, 1880. 



Hon Chas. Speck in the chair. Fifteen members and visitors 

 present. 



Mr. Nipher made an experiment showing the formation of a 

 vortex in water, a section of the apparatus being represented in 

 the cut. 



A wide-mouth receiver (^ B) with a tubulure (^) is placed with the 

 latter down, and a glass tube C^- d) with cork is fitted into the tubulure, 

 which thus serves for an escape for water. Water is run into the receiver 

 by a rubber tube («), so arranged as to throw 

 the water into rotation. The water was run 

 in from the hydrant with a pressure of 50 or 

 60 ft. A tall, narrow bell glass (C) was then 

 placed centrally over the vortex formed, as 

 shown, and an exhaustion of the air in C then 

 took place, the water rising in C until the 

 whole length of the vortex was about 30 inch- 

 es. Its diameter at the top was about half 

 an inch and it rapidly diminished in size, be- 

 coming apparently not over a tenth of an inch 

 in diameter at a depth of six inches, and at 

 the bottom (as the limit of exhaustion was 

 reached) the vortex was represented by a fine 

 filament, the lower end of which was con- 

 tinually breaking oft" and passing rapidly 

 down the discharge tube. When the bell glass 

 (C) is not symmetrically over the discharge 

 tube, the vortex is more or less curved and 

 sways slowly in a most beautiful manner. 

 Cochineal tincture poured into the outside 

 vessel, or bits of wood introduced into the 

 mouth of C, show the path of the water particles around the vortex. A 

 thin splinter introduced into the discharge tube mounts quickly to the top 

 with the shortening vortex when b is closed for a moment, and darts 

 quickly down again when b is opened. It is intended to arrange the appa- 

 ratus so that three or more of such vortices can be made in one vessel, in 

 order to show how they act upon each other under various circumstances. 

 The beauty of the experiment was marred somewhat by reason of the 

 turbidity of the hydrant water. In making the experiment care should 

 be taken to make the tube b d fill with water. The velocity of outflow can 

 be regulated somewhat by plunging the tube b into a vessel of water, 

 bringing the lower end of the tube near the bottom. If desired, the tube 

 can also be throttled by a perforated cork. 



