Mr. R. H. Ridout's Laboratory Notes. 439 



matic experiment of M. Clement Desormes, is based on the 

 assumption that the velocity of the fluid gradually decreases 

 as it approaches the edges of the disks. To determine how 

 far this was generally true, I took an outer cone A of 

 4 inches diameter at base with angle of 60° at apex, and an inner 

 cone B upon same base with angle of 120°. For the velocity 

 of the liquid to diminish between the apex of B and base of A, 

 the cones must be separated nearly J inch. Using water at 

 varying pressure, in no case did attraction take place at more 

 than jq in., where the velocity must increase towards the out- 

 let. I find also that the presence of the attracted cone, ball, 

 &c. diminishes the pressure in the supply-pipe, as shown by a 

 water-guage attached to the latter. Hence the presence of the 

 cone &c. facilitates the efflux. 



Laboratory Notes. 



Apparatus for showing Electrolysis of Water. 



A glass bolthead of 30 or 40 oz. capacity is stopped with an 

 india-rubber cork carrying two glass tubes, which contain her- 

 metically sealed platinum wires, projecting an inch at the inner 

 end and terminating in binding-screws at the other. The vessel 

 is filled one fifth full of acidulated water, boiled, and the stopper 

 inserted to cause a vacuum when cold. On connecting with 

 two " Grove " cells, the bubbles of gas so expand as to make 

 the whole liquid appear to boil. With either a single "Grove," 

 " Bunsen," "bichromate," or "Leclanche" cell continuous 

 decomposition may be obtained. When sufficient gas has 

 collected to impair the vacuum it may be restored by boiling. 



Experiment showing Cohesion in Liquids. 



A shallow tray 6" x 2", open at one end and lipped, is sup- 

 ported on three levelling-screws, the lipped end being slightly 

 higher than the other. A quantity of mercury placed in the 

 tray falls to the lower end ; but if now a little more be added 

 to make it flow over the lip, the cohesion is such as to enable 

 the descending stream to drag the remainder up the inclined 

 plane. Water gives similar results ; but, from the difficulty 

 of getting a surface which will long remain unwetted, the 

 results are not so satisfactory. 



Production of a Musical Note in a Continuous Tube. 



In most wind instruments the sound results either from the 

 movement of a solid body, or the air has the choice of two 

 directions, which it alternately takes. I find, however, that it 

 is possible to produce a good note from a tube J to | inch in 



