January 26th, 1897.~] Proceedings. xxvii. 



General Meeting, January 26th, 1897. 



Professor Harold B. Dixon, F.R.S., in the Chair. 



Mr. J. Grossmann, Ph.D., Harpurhey Chemical Works, 

 Manchester, and Mr. J. F. Tristram, M.A., Hulme Grammar 

 School, were elected ordinary members. 



Ordinary Meeting, January 26th, 1897. 



Professor Harold B. Dixon, F.R.S., in the Chair. 



The thanks of the members were voted to the donors 

 of the books upon the table. 



Mr. Alfred R. Bennett, M.I.E.E., read a paper 

 entitled: "A Convection Scope and Calorimeter," which 



was communicated by Mr. William Thomson, F.C.S. 



Mr. Bennett described how he had devised a small and 

 exceedingly sensitive motor, which begins to revolve the 

 moment it is exposed to daylight in the open air, whether 

 the sun be shining or not, and which will also work all night 

 in clear weather. The delicacy of the motor is such that it 

 is affected by the radiant heat of moonlight. The motive 

 power is due to convection currents caused by the radiant 

 heat of daylight striking through a glass shade, with which 

 the instrument is covered ; the glass is not heated, but the 

 metal surfaces of the instrument are, and air is consequently 

 expanded on the motor surfaces, and condensed on the glass, 

 the resulting difference of temperature setting up a convec- 

 tion current which does not cease so long as the instrument 

 is exposed to the radiant heat due to visible rays. 



Descriptions were given of modifications by which surplus 

 heat is automatically stored during the day and employed to 



