350 



Presents. 



[May 26, 



was not aware that importance was attached to this point, but I have 

 since repeated many of my former observations, holding the pillar in 

 the hand. The results are certainly stronger, but the extra heat 

 imparted to the apparatus is in my opinion sufficient to account for 

 this. M. Thore brings forward many new and ingeniously devised 

 experiments to prove that heat cannot be considered the cause of the 

 movement. He exposes the instrument to the full sun and then 

 brings it into a cool dark room ; he suspends it over boiling water ; 

 he places a large block of ice between the cylinder and the observer ; 

 he similarly interposes metallic vessels full of boiling water between 

 the cylinder and observer (the observer not moving from his place in 

 front), and he tries the experiment in a hot chamber alternately 

 moist and dry, without finding the regularity of the movements inter- 

 fered with. I have tried most of these, and obtained results corrobo- 

 rating M. Thore's, but I have also tried the experiment of quietly 

 bringing near to the stationary cylinder a bottle of hot water and 

 observing the movement from a safe distance through a telescope, and 

 I find that the hot bottle is able to effect rotation as well as the 

 observer. 



Among the curious observations mentioned by M. Thore is this : — 

 Placing the pillar in front of the cylinder (between it and the 

 observer), if the pillar is held with the right hand the movement is 

 clockwise, and if the left hand is used the rotation is counter-clock- 

 wise. The right hand is stronger in its effects than the left hand in 

 the proportion of 2 to 1. 



M. Thore has given in addition a large number of curious and 

 interesting observations, using two, three, and more movable 

 cylinders and recording their movements under a great variety of 

 circumstances. I admit I do not see at once how all these are to 

 be explained on the molecular bombardment theory. But this theory 

 has not yet explained all the anomalous results I have recorded in 

 my papers on " Repulsion resulting from Radiation," although 1 

 believe it capable of doing so ; and I therefore think that it is not 

 necessary to call upon a new force to explain any of M. Thore's 

 results which radiation does not yet seem able to account for. 



The Society adjourned over the Whitsuntide Recess to Thursday, 

 June 9th. 



Presents, May 26, 1887. 



Transactions. 



Buckhurst Hill : — Essex Field Club. The Essex Naturalist. No. 4. 



8vo. Buckhurst Hill 1887. The Club. 



Leeds : — Naturalists' Club. Transactions. 1886. 8vo. Leeds 1886. 



The Club. 



