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systematic registration of the variations of temperature, as 
the growth of corn, &c., depended as much on the chemical 
effect of light as on the temperature of the air. 
Mr. Baxendell regarded the subject as a new department 
in meteorology, and one likely to yield results of considerable 
interest and importance. 
Mr. Parry suggested that it was desirable to have obser- 
vations made at more than one station, and at a distance 
from Kew. 
Dr. Roscoe stated that he hoped in a short time to perfect 
apparatus for effecting the registration of the chemical 
changes in the light by means of self-acting apparatus, so as 
to lessen the labour of making the observations. 
It was suggested that a simple photometer would be useful 
to photographers working with dry plates, and Dr. Roscoe 
said he would endeavour to carry out the idea. 
