lights of less illuminating power individually, thereby immensely 

 lessening the economy. This is the main difficulty : another lies in 

 the fact that in this sub-division of the light, the incandescent plan 

 must be used. Now platinum and carbon are the only substances, 

 except the costly and rare metal iridium, which can resist without 

 fusion the very high temperature necessary. But platinum in time 

 becomes brittle and breaks or fuses, and carbon burns away if heated 

 in the air, or disintegi-ates if in a vacuum. Edison in America 

 has so far only re-discovered facts which are already well known, 

 and which have been elaborately tried for more than 30 years. The 

 only novelty which has been produced is an arrangement for 

 generating electricity by the motion of a large tuning-fork worked 

 by a steam engine ; but this is probably the most inefficient machine 

 for the purpose which has ever been constructed. 



Note January, 1880: Mr. Edison admitted in December, 1879, that up 



to that date, when he tried the baked cardboard, nothing had been discovered 

 of any importance, and that all his attempts so far had been fruitless. After 

 seven weeks' trial the tuning-fork arrangement was discarded as " utterly 

 worthless." — J. W. W. 



APEIL 1st. 



Dr. Aejisteong, F.E. S., Secretary to the Chemical Society, 

 read a Paper on " Starch : its Formation and Functions in Plant 

 Life : "— 



Starch is a white substance which turns violet when iodine is 

 applied to it. On examining with a microscope the cells of the 

 young leaves of a plant, it is found, as a rule, that their contents are 

 not homogeneous, but that they contain a number of green granules 

 to which the colour of the leaf is owing, the rest of the cell-contents 

 being colourless. When a solution of iodine is added, these granules 

 are coloured violet, and hence it is inferred that they contain starch. 

 When, however, growmg plants are placed for a time in the dark, 

 the starch invaiiably disappears from the granules, but it as 

 invariably reappears when the plant is restored to the light. 



