1880.] Elementary Principles of Animal Mechanics. 



219 



Dr. Schiibeler, of Christiania, on " The Effect of Uninterrupted Sun- 

 light on Plants in the Arctic Regions." These observations fully 

 confirm the conclusion indicated by my experiments with electric 

 light. Not only are plants able to grow continuously, according to 

 Dr. Schiibeler, but when under the influence of continuous light they 

 develop more brilliant flowers and larger and more aromatic fruit than 

 under the alternating influence of light and darkness, whereas the 

 formation of sugar appears to be dependent chiefly upon temperature. 



It would follow from these observations, that with the aid of stoves 

 and electric light, fruit, excelling both in sweetness and aroma, and 

 flowers of great brightness, may be grown without solar aid. Dr. 

 Schubeler mentions' that in removing an Acacia plant from the dark, 

 and placing it under the influence of the arctic midnight sun, the 

 leaves opened slowly, and it is interesting to observe that the same 

 effect took place when an Acacia lophantha was placed (in the open 

 air) under the influence of my midnight lamp. 



March 11, 1880. 

 THE PRESIDENT in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. The Croonian Lecture. — " On some Elementary Principles 

 in Animal Mechanics. No. IX. The Relation between 

 the Maximum Work done, the Time of Lifting, and the 

 Weights Lifted by the Arms." By the Rev. Samuel 

 Haltghton, M.D. (Dubl.), D.C.L. (Oxon.), F.R.S., Fellow of 

 Trinity College, Dublin. Received February 28, 1880. 



In the preceding note (No. VIII) I have shown that, in lifting 

 weights at a fixed rate with the arms, until fatigue sets in, the follow- 

 ing equation, deduced from the law of fatigue, is complied with, very 

 closeiy : — 



<1+W - A (1) 



