612 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



motion of one liquid in another has a character of its own. Thus if 

 a little olive oil be shaken to an emulsion with a large quantity of 

 water, the minute drops move, but slowly and not with a jerky 

 motion. Similarly a few drops of water mixed with a large volume 

 of oil, display the same character of motion. 



This motion cannot be attributed to currents in the liquid, for its 

 nature is such as to preclude this explanation. It is in no sense 

 regular, or in one direction. 



The author thought it worth while to compare the relative size of 

 such particles with those estimated for molecules, and likewise the 

 amplitude of their motion with that of molecular vibration. 



The diameter of a molecule, according to Sir W. Thomson, lies 

 between the millionth and ten-millionth of a millimetre. The 

 diameter of an active particle is about or below the two-thousandth 

 of a millimetre. With this size the pedetic motion is slow and 

 infrequent. If we take the larger diameter for the molecule, then 

 the diameter of the molecule is greater than that of the particle as 1 is 

 to 500, and the mass, suj)posing them to be of equal specific gravity, 

 as 1 to 125 millions. 



If molecules do not coalesce and move as a whole, then they would 

 appear to have no possible power of giving motion to a mass so much 

 larger than themselves, but that molecules have arrangement is pro- 

 bable, owing to the power which some liquids possess of rotating the 

 plane of polarized light. 



Clerk-Maxwell supposed for some time that the attraction of two 

 molecules vai'ies inversely as the fifth power of the distance. If 

 attraction at distance 2 is 1, attraction at distance 1 would be 64. 

 Why do not all molecules therefore coalesce ? probably, because their 

 own proper motion, of which heat represents the high harmonies, 

 causes them to fly apart again. The wave-length of that motion is 

 not so minute, and although we have no means of ascertaining the 

 amplitude of such vibrations, still their rate is so prodigious as to 

 give rise to an almost incredibly forcible impact. 



Ady, J. E. — Exhibition of some Microscopical Preparations of Bone. 



Proc. Zool. Soc. Lond., 1883, p. 74. 

 Bell, F. J. — Exhibition of and remarks upon some Microscopical Preparations 

 obtained from the Zoological Station at Naples. 



Froc. Zool. Soc. Lond., 1883, p. 47. 

 Caldebon t Arana. — Nota sobre la extraccion y coleccion de las conclias mieros- 

 copicas de moluscos y foramiuiferos. (Note on the extraction and collection 

 of the microscopic shells of moUusca and foraminifera.) In part. 



An. Soc. Esp. Hist. Nat, XII. (1883), Actas, pp. 33-6. 

 Carter, H. J. — On the Microscopic Structure of thin slices of Fossil Calcispon- 



[Contains directions for grinding down a slice of a calcareous fossil. Post."] 

 Ann. ^ liar/. Nat. Hist., XII. (1883) pp. 26-80. 

 Cathcaet, C. W. — New form of Ether Microtome. [Supra, p. 597.] 



Journ. A7iat. <^ Physiol., XVII. (1883) pp. 401-3. 

 Chabry, L. — Note sur quelques proprie'tes du Bleu de Prusse. (Note on some 

 properties of prussian blue.) 



Journ. de I'Aiiat. et de la Physiol., XVIII. (1882) pp. 503-9. 



