424 PHILOSOPHICAL TRANSACTIONS. j^ANNO 1708. 



whose two opposite superficies have the greatest attractive forces ; this inte- 

 mediate corpuscle will unite to itself the particles of the fluid ; and many such 

 corpuscles, diffused through the fluid, will form all its particles into a compact 

 body, and reduce the fluid into ice. 



Theorem 30. — If any body emit a large quantity of effluvia, whose attractive 

 forces are very strong ; when these effluvia approach any lighter body, their at- 

 tractive forces will at length exceed the gravity of that body, and the effluvia 

 will attract that body up towards themselves : and since the effluvia are much 

 more copious at smaller, than at greater distances from the emitting body, the 

 light body will always be attracted towards the denser effluvia, till at length it 

 adhere to the emitting body. Hence a great many of the phaenomena of elec- 

 tricity may be explained. Perhaps some may object against this doctrine, and 

 say, that if this attractive force were inherent in all matter, then the more 

 ponderous bodies, and such as contain a greater quantity of matter in a given 

 space, would attract more than the less ponderous, which is repugnant to 

 experience ; but this objection may be easily answered in this manner : the par- 

 ticles of the last composition, (to which alone the attractive force is ascribed) 

 when placed close to each other, may constitute a ponderous body, though of 

 themselves they may be more rare than the particles of the last composition, 

 that constitute a light body, being more remote from each other, and having 

 more and larger pores. Several other phaenomena of nature, Mr. Keill thinks, 

 may be explained by the same principles ; as the ascent of the sap in plants and 

 trees; the determinate and constant figures of leaves and flowers, and their 

 specific virtues, &c. As also several things that duly occur in the animal 

 economy ; particularly what relates to the circulation and secretion of the 

 fluids, and which depend on the same qualities of matter : and hence the 

 theory of diseases, and the effects of medicines are best investigated. 



Microscopical Observations on the Tongue, By Mr, Anthony Van Leuwenhoeck, 



F.R,S. N°315, p. HI. 



Having taken some neats' tongues, and separated some thin parts of the 

 outer skin, where I conceive is the place that admits the juices into the tongue, 

 by which that sensation is produced which we call the taste ; I separated those 

 aforesaid external particles as well as I could from those that lay under them, 

 and observed that the latter, that is, the internal, were furnished with a multi- 

 tude of pointed particles, the lops of which were mostly broken off, and 

 remained sticking in the outer skin : and one of those internal particles of the 

 tongue, before a microscope, appeared as a transparent body, something larger 

 than a thimble, having small internal holes or cavities, through which a greater 



