BAIRD &TXTLOCK (LONDON) LTD. 





4833 T Simmance & Abady's Ventilating Hygrometer 



3 3 



4834 



4834 T C. G. Paterson's Rotator. 



This spinner or rotator, which lias been designed by Mr. C. C. Paterson, of the National Physical Laboratory, 

 is of the mercury bath type, and is arranged to revolve lamps suspended vertically at a speed varying from 400 

 to 30 revolutions per minute. That it is handy may be gathered from the fact that it is made to drop into the 

 central tube of the photometer carriage, and that the total dimensions are 417 millimetres high by 266 millimetres 

 outside (including motor). The construction is such that owing to the mercury bath and amalgamated copper 

 terminals, there is practically no drop in the voltage nor between the rotator and the voltmeter. 



This is the apparatus used by the National Physical Laboratory. 



Price 30 







CROSS STREET HATTOTST GARDETST, E-C 



