[miller-kenrick] researches IN PHYSICAL CHEMISTRY 215 



enables the percentage of deaths to be ascertained with fair accuracy 

 by a few minutes' work; plates can then be poured if needed, with 

 the certainty that none will be wasted; or microphotographs may 

 be made and counted at leisure. The time needed for a given poison 

 to make a yeast cell stainable is a little longer than that required to des- 

 troy its power of reproduction; the nature and extent of this dif- 

 ference are now being studied. {Winter 1911-1912). 



No. 18. W. Lash Miller: — The chemical philosophy of the High- 

 school text books. — Hand in hand with the study of chemical equili- 

 brium, the idea of continuity between chemical and "physical" 

 changes has entered chemistry, and is transforming it. The high- 

 school text-books, however, as a class, in their tendency deny this 

 continuity in toto. In order to be "up to date," however, they in- 

 clude much of the experimental evidence which has forced this con- 

 ception into the science, with the result that they contradict them- 

 selves, and involve the whole subject in a maze of vagueness and 

 mystification wholly foreign to the scientific spirit. 



Numerous illustrations are given, and the importance of a change 

 is insisted upon. At present, children are being trained to accept 

 obscure, ecjuivocal, and dogmatic statements in place of clear and 

 exact thought, and high-school "chemistry" is fast earning a place 

 among that group of pedagogic processes which Huxley characterized 

 as the "direct and preventable cause of most of the world's stupidity."* 



No. 19. J. C. McRae: — The distribution of temperatures during the 

 solidification of undercooled liquids. — -By means of a fine thermocouple 

 and a quick-acting oscillograph, the temperatures in a supercooled 

 solution were measured at different distances in front of an advancing 

 column of crystals. When the crystals once reached the wire, of 

 course, the temperature remained stationary until the solidification 

 was complete. A differential equation was set up to describe the 

 temperature distribution. {Winter 1911-1912). 



No. 20. W. B. Wiegand: — The effect of an external heat source 

 on the rate of propagation of fiâmes. Mr. Evans' experiments (see 

 above) were checked and amplified b}^ studying the effect of heat 

 supplied by a gold wire heated by a measured curient and held at 

 fixed distances in front of the flame. Platinum could not be used 

 because of its catalytic action. {Winter 1911-1912). 



No. 21. Frank B. Kenrick: — Lantern experiments on reactions in 

 non-homogeneous systems. — -{i) Working model of the "piston and 

 cylinder" used in thermodynamic argumentation; the main difficulty 

 was in making an air-tight frictionless joint between the piston and 

 the cylinder. This was overcome by a mercury packing, kept in place 

 by surface tension, (n) Modification of the above to shew the proper- 

 " *Science, 34, 257^63 (1911). 



