March 29, 1918] 



SCIENCE 



313 



vestigating some of the scientific questions 

 which have arisen in the course of the manu- 

 facture of compressed yeast under present war 

 conditions. The university has appointed the 

 first fellow on this foundation, who is now en- 

 gaged in research upon the problems. 



Dr. WiLLUM M. Jardi.ne has been appointed 

 president of the Kansas State Agricultural 

 College and entered upon his duties on March 

 1. Dr. Jardine had been connected with the 

 college for about eight years, first as professor 

 of agronomy and for five years as dean of the 

 division of agriculture and director of the 

 Agricultural Experiment Station. 



Dr. F. E. Denny, of the University of Chi- 

 cago, has been appointed research assistant in 

 horticulture in the Oregon Agricultural Col- 

 lege, to fill the vacancy left by the resignation 

 of Mr. Magness, the appointment to take ef- 

 fect on April 1. 



Dr. Helen M. Gilkey, of the University of 

 California, has been appointed assistant pro- 

 fessor of botany and curator of the herbarium 

 in the Oregon Agricultural College, to succeed 

 the late H. S. Hammon. 



Dr. Ethel M. Terry, of the department of 

 chemistry of the University of Chieago, has 

 been appointed to an assistant professorship. 



Dr. Fred W. Upson, for the past four years 

 professor of agricultural chemistry in the Ne- 

 braska College of Agriculture, will, on June 1, 

 become head of the department of chemistry 

 in the University of Nebraska. A chemical 

 laboratory which is modern in every respect, 

 will be ready for occupancy at that time. 



DISCUSSION AND CORRESPONDENCE 



AN APPARENTLY NEW PRINCIPLE IN THE 

 FLOW OF HEAT 



Suppose a number of horizontal metallic 

 strips arc maintained at constant tempera- 

 tures, the first one at a low temperature, the 

 next at .successively higher temperatures, the 

 last one being at the maximum temperature 

 of a Bunsen flame, say a white heat. Let them 

 all be of the same metal and have like sur- 

 faces. 



Now suppose the same Bunsen flame be ap- 

 plied under like conditions to each strip. Ac- 



cording to text-books and the laws of the 

 transference of heat as usually taught, one 

 would be led to believe that the coldest one 

 should absorb the heat from the flame most 

 rapidly, the next one less rapidly, and so on. 

 Tests made by the writer, however, show this 

 to be an error and that up to a certain high 

 temperature exactly the reverse is the case; 

 the coldest one will absorb the least amount 

 of heat from the flame, the next hotter one 

 will absorb more and so on up to a temperature 

 at which the rate of absorption will be a 

 maximum, after which it diminishes again, 

 becoming zero for the one whose temperature 

 is equal to that of the flame. 



As stated in the premises, the heat which 

 enters the metal from the flame is supposed to 

 be conducted away as fast as it enters, and 

 it is this heat which is measured. This could 

 be carried out by using flat-bottomed iron cups 

 or crucibles containing various materials 

 having successively higher but fixed boiling 

 points, say like liquid air, water, sulphur, 

 zinc, etc. 



When a very hot gas, like that in a flame, 

 impinges on a relatively very cold surface 

 from which the heat is led off as fast as it 

 enters, like in the boiling of water by flame 

 heat, a peculiar phenomenon takes place in 

 that the equivalent of a very thin film of 

 extremely high thermal resistance is formed 

 on the surface exposed to the flame. Con- 

 sidered as a thermal resistance, the writer 

 finds that for a constant temperature flame 

 its resistance decreases rapidly as the temper- 

 ature of the absorbing surface increases, con- 

 trary to what would have been supposed. The 

 transmission of heat therefore increases as the 

 absorbing surface becomes hotter and reaches 

 a maximum which appears to be roughly when 

 the drop of temperature from the flame to the 

 surface is equal to that from this surface to 

 the constant temperature boiling liquid ; the 

 transmission then must fall again, becoming 

 zero when the temperature of the boiling 

 liquid is equal to that of the flame. This in- 

 crease of temperature of the surface (to about 

 a red heat when water is being boiled) can be 

 brought about by inserting a properly pro- 



