December 3, 1920] 



SCIENCE 



529 



1^><^ =31.25. 

 12 X 1.2 



Find the time required with, an electric cur- 

 rent of 10 K and a potential of 100 to heat 

 unit mass of helium (atomic weight, 4) 

 through a temperature interval of 10 M, at 

 constant pressure. (The specific heat of a 

 monatomic gas at constant volume is 3/2.) 

 Answer : 



j: X 10' X (f + 1) 

 10* X 100 



= 62.5 see. 



Find the mass of copper (valence 2, at.wt. 

 63.57) that would be deposited by a current of 

 10 K in 1,000 sec. Answer: 



63.57 X 10^ X 1,000 

 2 X 10' 



: 0.318. 



Find the capacity of a condenser with 100 

 sheets of dielectric (of dielectric constant 2) 

 each of unit area and thickness 0.01. Answer : 



100 X 1 X 2 = 2 X 10-' 

 109 X 0.01 =20m. 



Find the inductance of a coil of 100 turns 

 wound on a closed core of iron ,of permeability 

 1,000, of cross section 0.2 X 0.2 and length of 

 magnetic circuit 4. Answer: 



100 X 1.000 X .2 X .2 



10" 



10» X 4 



Find the magnetic energy of the core when 

 a current of 1 K is passing through the coil. 

 Answer : 



I X (10')2 X lO-< = 50. 



In conclusion, it should be noted that the 

 foregoing is primarily a description of a 

 method of deriving a system of units, and that 

 a system of substantially equal convenience 

 could be devised with an other than decimal 

 arithmetic, a different unit of time or another 

 basis of atomic weights. 



SUMMARY 



1. On the common foundation of the English 

 and metric systems of units there can be con- 

 structed a system superior to either. 



2. Its bases are (1) the mean solar second, 

 (2) a length, of 29.986 cm. and (3) a mass of 

 25.636 g. 



3. Tables of the relation of the various units 

 in this system to the corresponding metric 

 units are given. 



4. A single set of units serves for both engi- 

 neering and scientific purposes. 



Elliot Q. Adajss 

 BuKEAU or Chemistry, 

 Washington, D. 0. 



PALEONTOLOGY AND PRAGMATISM 



Two recent publications of the United 

 States National Museum admirably illustrate 

 a phase of the scientific activities of the gov- 

 ernment to which I have long thought of call- 

 ing attention, since they are accomplished 

 without noise or press notices and are of im- 

 mense value to the peojile as a whole in ad- 

 dition to their intrinsic scientific worth. 



The publications to which I refer are North 

 American Early Tertiary Bryozoa, by Canu 

 and Bassler, constituting Bulletin 106, and 

 Contributions to the Geology and Paleon- 

 tology of the Canal Zone, by T. "VVayland 

 Vaughan and associates, constituting Bulle- 

 tin 103. More particularly I wish to refer to 

 the work of Canu and Bassler on the Bryozoa, 

 Joseph A. Cushman on the Foraminifera, 

 Marshall A. Howe on the calcareous algae, 

 and T. Wayland Vaughan on the corals. 



These are all groups of organisms whose 

 habits are exceedingly interesting and whose 

 forms are often highly artistic, but none of 

 which furnish food for commercial fishes or 

 humanity, or are objects of trade,^ or yield 

 any gums, wax, gems, or minerals that might 

 make them seemingly worth while to the man 

 in the street. 



The Bryozoa are inconspicuous colonial 

 animals, some of them with a beauty all their 

 own, but seldom appreciated since they require 

 magnification in order to be seen to advan- 

 tage. Some are usually included in amateur 

 collections of so-called sea weeds, hut to the 

 average person a bryozoan is as unknown as a 

 native of Mars. The recently installed sea 



1 The red coral of oommeTee and its imitations 

 are exceptions, but these are European and not 

 American products and do not affect the force of 

 the statement. 



