August 19, 1910] 



SCIENCE 



251 



We have not studied the matter sufficiently to 

 hazard an explanation. The simplest working 

 hypothesis would be that the difference ob- 

 served is an expression of the greater reducing 

 activity of the unfertilized eggs. It may be 

 imagined, however, that the iodine is disposed 

 of in the unfertilized eggs by the lipoids of the 

 plasma membrane. In the fertilized eggs 

 these lipoids may be redistributed or other- 

 wise changed in the membrane, and this 

 change in the lipoids may lead to the increase 

 in permeability to certain substances. This 

 supposition would tend to bring our iodine 

 experiments into relation with the other ob- 

 servations on permeability. 



E. P. Lyon 

 L. F. Shackell 



FiSHEBIES LaBOEATOET, 



Beaufoet, N. C, 

 July 26, 1910 



■v A peculiar heat phenomenon 



The phenomenon described here was dis- 

 covered unexpectedly in connection with a 

 lecture experiment on vapor pressure. An in- 

 verted barometer tube A is arranged so that 

 the space above the mercury is filled with 

 water and water vapor. A glass tube B sur- 

 rounds the barometer and allows steam to 

 enter at the top, surround the barometer, and 

 pass out at the bottom. As the vapor is 

 warmed by the steam, it increases in pressure 

 and pushes the mercury down. 



The incoming steam does not pass immedi- 

 ately through the tube, but works its way 

 gradually downward, its progress being noted 

 by the condensation on B. The mercury col- 

 umn follows the condensed steam line regu- 

 larly until it is depressed about 12 cm., when 

 it begins to oscillate. Thus, if B represents 

 the lower end of the condensed steam, the os- 

 cillations take place symmetrically on either 

 side of B between E and F, the distance EF 

 being from 2 to 4 cm. In the meantime, the 

 steam line progresses steadily downward; the 

 oscillations following it closely and becoming 

 more rapid and of less amplitude until they 

 finally cease near the bottom of the tube. 



The action is a close approach to that of a 



Carnot's engine. The substance goes through 

 a complete cycle during each oscillation, ab- 

 sorbing heat at steam temperature and giving 

 it out to the cold tube below B. It becomes 

 cooled also by the work it does in expanding. 

 It is then pushed back up the tube from below, 



Fig. 1 



its pressure being less than when expanding 

 because its temperature is less. Therefore 

 more work is done during expansion than con- 

 traction. The indicator diagram is probably 

 of the form shown in Fig. 2. 



The oscillations of the mercury column 

 would tend to stop when the tube below B be- 



