216 



SCIENCE. 



[N. S. Vol. XVI. No. 397. 



thors, who made an analysis of the water. 

 No especial phenomena were noted preced- 

 ing or during the precipitation ' except an 

 unusually black cloud and a heavy down- 

 pour of rain, accompanied by a darkness 

 so dense as to necessitate the use of lamps 

 for half an hour.' About sixty per cent. 

 ■of the total residue {8S parts per million) 

 ■was organic matter, largely soot. The 

 •chlorine content (19.144 parts per mil- 

 lion) showed an unusual amount of sodium 

 chloride. The residue contained traces of 

 several metals, as calcium, iron, manganese, 

 zinc and aluminum. The other constitu- 

 ents indicated ordinary rain. The situa- 

 tion and amovint of fuel burned in the 

 place, as well as the time of year, preclude 

 accounting for the fluorescent black rain 

 l)y local contamination such as observed in 

 numeroiis cases b.y Angus Smith and Phip- 

 son and lately by Irwin, who examined the 

 snowfall in Manchester (/. S. C. In., 21, 

 533). 'WTiile it is well known that unusu- 

 al impurities in rain, snow, etc., often oc- 

 •cur and the sources of contamination may 

 "be traced great distances, no opinion is 

 hazarded as to the cause of this phenome- 

 non. All such incidental observations de- 

 serve chronicling as did the ' blood rain ' 

 reported (by Passerini) to have fallen at 

 Florence in March of last year {L'Orosi, 

 "24, 325) and the 'dust fall' in Europe the 

 sajne month (reported by Hellmann and 

 Meinardus). 



C. B. Williams, 



Secretary. 



BLUE FOX TRAPPING ON STEE PRIBILOF 

 ISLANDS. 



Science for January 26, 1900, contained 

 an account of the method of trapping blue 

 foxes employed on St. George Island of the 

 Pribilof group and of the efforts, there 

 and elsewhere, to render the blue fox 

 polygamous by killing males only. Near 

 the end of the article it was said 'The out- 



come of these experiments will be awaited 

 with much interest, and if by a little arti- 

 ficial selection and environment a naturally 

 monogamous animal can be rendered po- 

 lygamous, the supply of blue fox furs will 

 be materially increased.' 



The experiment has been continued and, 

 by the courtesy of the Treasury Depart- 

 ment, some of the results are here given. 

 From the fact that for the last four sea^ 

 sons all females taken in the traps have 

 been released it might naturally be ex- 

 pected that there should now be a marked 

 preponderance in the number of females. 

 That such is not the case, however, is shown 

 by the fact that during the trapping sea- 

 son of 1900-1901 there were taken 614 

 males and but 690 females, an excess of 

 only 80 after four years of killing males 

 only. A glance at the subjoined table 

 •giving the I'esults of each year's trapping 

 shows that not only has there been no 

 increase in the proportion of females to 

 males, but that in one year the number of 

 males taken actually exceeded that of the 

 females by 89. 



Number of Foxes Taken o>' St. George Islai^d. 



Excess of 



Males. Females. Total. Females. 



1897, 102 324 426 222- 



1898-9. 478 389 867 —89 



1899-00, 468 487 955 19 



1900-02, 614 690 1304 76 



At first sight it might appear that there 

 had been a noteworthy increase in the 

 total number of foxes, but a large portion 

 of this apparent gain is due to the effort 

 that has been made to ascertain the num- 

 ber of foxes on St. George, and in the 

 spring of 1901 trapping was carried on 

 both at the 'fox house' and in other places 

 after the close of the regular season. All 

 these animals were marked and released, 

 so that no fox was counted twice. That there 

 has been some slight gain in the number 

 of foxes seems probable, but a glance at the 



