October 10, 1913] 



SCIENCE 



523 



things, lie anticipated and realized the attain- 

 ment of regular reflection from a sufficiently 

 dense absorbing vapor; while to the public in 

 America he is known as the inventor of a 

 practical method of thawing frozen pipes by 

 an electric current. The idea of a gigantic 

 telescope in the form of a sunk well, with a 

 revolving pool of mercury at its base to consti- 

 tute a truly parabolic mirror, may not be a 

 new one, but Professor Wood has taken it out 

 of the region of the chimerical and shown that 

 it is possible, even if not practically useful. 

 We in this country have reason to envy the 

 splendid resources which the munificence of 

 citizens in America, and of governments else- 

 where, places at the disposal of scientific ex- 

 plorers, and we honor and admire the use 

 which is being made of those resources in 

 every branch of science. As one of the most 

 brilliant experimental physicists of the world, 

 I present for our honorary degree Robert 

 Williams Wood. 



THE NEW INTERNATIONAL DIAMOND 

 CARAT OF 300 MILLIGRAMS 



The importance of having uniform weights, 

 and the great practical disadvantages result- 

 ing from the international use of a perplexing 

 variety of standards, have long made them- 

 selves felt in the diamond market. This sub- 

 ject has just been very fully treated in a 

 paper read before the American Institute of 

 Mining Engineers, at the New York meeting, 

 February, 1913, and at the Butte meeting, 

 August, 1913.^ 



Those unfamiliar with the system of weights 

 employed by diamond-dealers can scarcely ap- 

 preciate the confusion that has existed, and 

 the necessity for complicated calculations 

 thereby entailed. This state of things will be 

 best illustrated by giving here the equivalents 

 in milligrams and troy grains of the principal 

 standard carats as used in various trade 

 centers : 



^ ' ' The New International Metric Diamond Carat 

 of 200 Milligrams (Adopted July 1, 1913, in the 

 United States)," by George Frederick Kunz, New 

 York, N. T., author's edition, 21 pp. (pp. 1225- 

 1245 of the Trans, of the Soc. of Min. Eng.). 



Milligrams Grains Troy 



Turin 213.5 3.29480 



Persia 209.5 2.23307 



Venice 207.1 3.19603 



Austro-Hungary 206.1 3.18060 



France (old) 205.9 3.17752 



France (later) 205.5 3.17135 



France (modern) 205.0 3.16363 



Portugal 205.8 3.17597 



Frankfort and Hamburg 205.8 3.17597 



Germany 205.5 3.17135 



East Indies 205.5 3.17135 



England and Brit. India 205.3 3.16826 



Belgium (Antwerp) 205.3 3.16826 



Russia 205.1 3.16517 



Holland 205.1 3.16517 



Turkey 200.5 3.09418 



Spain 199.9 3.08492 



.Java and Borneo 196.9 3.03862 



Florence 196.5 3.03245 



Arabia 194.4 3.00004 



BrazU 192.2 2.96610 



Egypt 191.7 2.95838 



Bologna 188.6 2.91054 



Internat. Carat, year 1875 205.0 3.16363 



New International Carat . 200.0 3.08647 



A glance over this table will serve to show 

 the crying need for the establishment of a 

 uniform and rational standard, and a prelim- 

 inary step in this direction was taken by the 

 Parisian jewelers in 1877, when they adopted 

 a carat of exactly 205 milligrams. However, 

 such a carat could never become an integral 

 part of the metric system, and as early as 1893 

 the writer suggested in a paper read at 

 Chicago before the International Congress of 

 Weights and Measures, held in connection 

 with the World's Columbian Exposition, that 

 a carat of exactly 200 milligrams should be 

 recognized as the standard carat weight. 

 Many years, however, elapsed before there was 

 any definite prospect that this idea would be 

 realized. The fact that in the early part of 

 1905 the German imperial government refused 

 to recognize the carat then used in Germany 

 as a standard weight, when requested so to do 

 by the German Federation of Jewelers, be- 

 cause such recognition would be a violation 

 of the laws prescribing the exclusive use of 

 the metric system, is said to have powerfully 



