PHYSICS: O. E. BUCKLEY 
683 
of parental alcoholism on the progeny in poultry. The additional data 
make still more certain the conclusions, first, that the progeny of alco- 
holized parentage (in poultry) while fewer in numbers is made up of 
individuals superior in physiological vigor, and, second, that this result 
is due to a selective action of the alcohol upon the germ cells. 
* Papers from the Biological Laboratory of the Maine Agricultural Experiment Station, 
No. 105. 
2 Pearl, R., Proc. Nat. Acad. Sci., 2, 380-384 (1916). Of. also for a fuller statement of 
the results Proc. Amer. Phil. Soc, 5S, 243-258 (1916). The complete report on the earlier 
stages of the work is in press in /. Exper. Zool. 
^ This term is defined in my former papers as *'the total number of days during which 
the two gametes making the offspring zygote have been exposed to alcohoUc influence while 
sojourning in the body of the treated individuals." 
* For summary and bibliography of earlier papers see Stockard, C. R., and Papanicolaou, 
G., A further analysis of the heredity transmission of degeneracy and deformities by the 
descendants of alcoholized mammals, Amer. Nat., 59, 65-88, 144-177 (1916), 
^ Tyson, H. H., and Schoenberg, M. J., Experimental researches in methyl alcohol in- 
halation, /. Amer. Med. Assoc., 63, 915-922 (1914). 
^ Poincare, L., Sur les dangers de I'emploi de I'alcool methyh'que dans I'industrie, Paris, 
C. R. Acad. Set., 87, 682-683 (1878). 
' Cf, for example Voltz, W., and Baudrexel, A., Ueber die vom tierischen Organismus 
unter verschiedenen Bedmgungen ausgeschiedenen Alkoholmengen. II. Mitth., Pfiugers 
Arch., 142, 47-88 (1911); and other papers in the same series. Also note similar data in 
Voltz, W., Forster, R., and Baudrexel, A., Ueber die Verwertung des Bierextraktes und des 
Bieres im menschlichen und tierischen Organismus. Ihid., 134, 133-258 (1910). 
" Cf. Ivanov, J., Action de I'alcool sur les spermatozoides des mammifdres (Premiere 
communication), C. R. Soc. Biol, Paris, 74, 480-482 (1913). 
AN IONIZATION MANOMETER 
By O. E. Buckley 
RESEARCH LABORATORY. AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND 
WESTERN ELECTRIC COMPANY 
Received by the Academy, November 13. 1916 
Heretofore the only manometers available for measuring extreme 
vacua have been the Knudsen manometer and the Langmuir molecular 
gauge. Both of these have serious disadvantages due to their delicate 
construction and slowness of action. A new manometer free from 
these objections and with a greater range of presssure than either has 
been developed. This manometer makes use of the ionization of gas 
by an electron discharge. 
The manometer consists of three electrodes sealed in a glass bulb 
which serve as cathode, anode, and collector of positive ions. The 
cathode may be any source of pure electron discharge such as a Wehnelt 
cathode or a heated tungsten or other metallic filament. The exact 
forms of the electrodes are not of great importance. The collector is 
