August 18, 1922] 



SCIENCE 



187 



Section 10: The unit of Luminous Intensity 

 is the International Candle, such as has resulted 

 from international agreement between the three 

 national standardizing laboratories^ of France, 

 Great Britain and the XJ. S. A. in 1909. 



This unit has been conserved since then by 

 means of incandescent electric lamps in the lab- 

 oratories which continue (or remain) charged 

 with its conservation. 



Section 12: The unit of Luminous Flux is 

 the Lumen. It is equal to the flux emitted in a 

 unit solid angle, by a uniform point source of 

 one international candle. 



Section 13 : The practical unit of illumination 

 is the Lux. It is equal to one Lumen per square 

 meter, or it is the illumination at the surface of 

 a sphere of one meter radius due to a uniform 

 point source of one interna'tional cajidle placed 

 at its center. 



As a consequence of certain recognized usages, 

 the illumination can also be expressed by means 

 of the following units: 



Using the centimeter as the unit of length the 

 unit of illumination is one lumen per square 

 centimeter, and is called the Phot. Using the 

 foot as the unit of length, the unit of illumina- 

 tion is one lumen per square foot, and is called 

 the Foot-Candle. 



FRENCH VITAL STATISTICS FOR I92|i 



The secretary (minister) of labor recently 

 published the official vital statistics for France 

 for the year 1921. It is an unfavorable report 

 from every point of view. The number of 

 births is below that of 1920, while the number 

 of deaths has increased; the number of mar- 

 riages has also decreased. The excess of births 

 over deaths, amounting to 159,790 in 1920, or 

 forty-one for each 10,000 inhabitants, de- 

 creased in 1921 to 117,023, or thirty for each 

 10,000 inhabitants. 



A comparison of the number of births and 

 deaths for the years 1921, 1920 and 1913 is 

 shown in the following table : 



Total Excess 



Year Population Births Deaths of Births 



1921 39,209,766 813,396 696,373 117,023 



1 These laboratories are the Laboratoire Cen- 

 tral d 'Electricite, Paris, the National Physical 

 Laboratory, Teddington, and the Bureau of 

 Standards, Washington. 



1 From the Journal of the American Medical 

 Association. 



1920 39,209,766 834,411 674,621 159,790 



1913 41,476,272 790,355 731,441 58,914 



The number of marriages, which reached an 

 unusually high figure in 1920 (623,869), 

 dropped in 1921 to 456,221, but it is still ap- 

 preciably higher than the number recorded in 

 1913 (312,036). 



An examination of the report brings out the 

 fact that whereas the number of living births 

 for each 10,000 inhabitants in 1920 was 213, 

 it fell in 1921 to 207 ; in 1913, it was 191. The 

 relative proportion of deaths has risen from 

 172 for each 10,000 inhabitants in 1920 to 177 

 in 1921, reaching about the same proisortion 

 that was recorded in 1913 — 176 for each 10,000 

 inhabitants. 



In 1921, sixty-seven of the French depart- 

 ments showed an excess of births over deaths, 

 the total amounting to 127,654, as compared 

 with seventy-three departments in 1920. On 

 the other hand, twenty-three departments 

 showed an excess of deaths over births, the 

 total amounting to 10,631, as against seventeen 

 departments in 1920. The seven departments 

 which, in 1920, showed an excess of births over 

 deaths but in which the balance in 1921 was 

 on the side of the deaths are : Aube, Cher, 

 Cote-d'Or, Maine-et-Loire, Orne, Seine-et- 

 Marne and Seine-et-Oise. In the department 

 of Isere, which in 1920 showed an excess of 

 deaths over births, the excess of births over 

 deaths in 1921 was 292. During the year just 

 preceding the war (1913), an excess of births 

 over deaths amounting to a total of 86,768 for 

 fifty-two departments was recorded, and an ex- 

 cess of deaths over births amounting to 27,854 

 was found in the thirty-eight other depart- 

 ments. 



The departments in which the excess of 

 births over deaths, in 1921, reached the highest 

 figures are : Nord, Seine, Pas-de-Calais, Finis- 

 tere. Moselle, Bas-Rhin, Seine-Inferieure, 

 C6tes-du-Nord, Morbihan, Haut-Rhin, Aisne, 

 Meurthe-et-Moselle, Ardennes and Bouches-du- 

 Rhone. In all these departments, with the ex- 

 ception of Aisne, Meurthe-et-Moselle and 

 Ardennes, the excess of births in 1921 was 

 much less than in 1920. 



The departments in which the excess of 

 deaths over births, in 1921, was highest are: 

 Yonne, Var, Gers, Lot, Lot-et-Garonne, Maine- 



