362 RoTfol Society of London. 



der to enable the author to pursue his inquiry into the com- 

 parative anatomy of these animals. In the stomach of the 

 borer he found a considerable quantity of matter, which 

 Mr, Tennant pronounced to be purely ligneous, and similar 

 to saw-dust. Notwithstanding this circumstance, and that 

 of the borer's burying itself always in timber, Mr. Home 

 concludes that wood is not properly its food, as it passes 

 undigested ; but that the animal, as well as the teredo gi- 

 gantea, draws its nourishment from the water. 



May 8. The President in the chair. — On this evening was 

 read a letter from Mr. O. Gregory, of the Royal Military 

 Academy at Woolwich, on sir Isaac Newton's definition of 

 the force of the lever, in which the author defended sir 

 Isaac's demonstration as the most simple and correct, against 

 all the objections urged by other mathematicians. Mr. G. 

 reduced his defence to propositions illustrated by figures, 

 and maintained that the force of a lever of the same length 

 and weight was equal in whatever other direction it might 

 pass from the fulcrum, as well as horizontal. 



May 15. The President in the chair. — An interesting let- 

 ter to the President, from Mr. T. A. Knight, on the invert- 

 ed action of the alburnous vessels of plants, was read. Mr. 

 Knight, discovering some facts in opposition to the senti- 

 ments of Hales and Duhamel, has taken much pains to con- 

 firm them by experiments, all of which have tended to prove 

 the truth of the opinions and observations which he has 

 communicated from time to time to the society, relative to 

 the circulation of the juices in plants, formation of buds and 

 sap-wood, and to vegetable physiology in general. In the 

 present cn-e his researches were directed to the roots of po- 

 tatoes, and he in consequence maintains that the formation 

 of all such roots is explicable only on the principle which 

 he has been endeavouring to establish, that of the inverted 

 action of the alburnous vessels in plants. His experiments 

 seem to have been conducted with his usual accuracy, and 

 leave little doubt of the truth of his observations and opi- 

 nions. Perhaps the discoveries of this ingenious philoso- 

 phical botanist may be found directly applicable to the use 

 of hot-house or green-house plants, in directing the gar- 

 1 dener's 



