Maech 25, 1904.] 



SCIENCE. 



505 



outer limit of the nebula -will be about haK 

 a million miles further out, the temperature 

 being zero at the outer limit. This means 

 that molecular motion will not there exist. 

 The forces there acting will be gravitation 

 and the repelling action of light waves from 

 the central nucleus. 



The entire mass of ISTeptune will exist in a 

 space far more highly rarefied than any 

 Crookes tube vacuum. 



It is, of course, possible for such nebulae to 

 exist, but it certainly is impossible to believe 

 that such a nebula can throw oS a system of 

 planetary bodies. The greater part of our 

 solar nebula must have existed as solid 

 meteoric matter, with a temperature ap- 

 proaching alsolute zero. Only the central 

 part, which is now represented by the sun, 

 was largely gaseous, and at a higher tempera- 

 ture. 



DISCUSSION AND COBRESPONDENGE. 



INSTABILITY OP THE WATEE SUPPLY OP THE KIO 

 GRANDE. 



To THE Editor op Science: In 1540 when 

 Coronado's men were exploring on the Eio 

 Grande, they reported arriving eighty leagues 

 below Tiguex at a place where the river van- 

 ished into the ground. Sorde Amerinds of 

 the region told them it reappeared again much 

 larger farther down. This they did not verify. 



As their report of this disappearance, I be- 

 lieve, has usually been ascribed to ' Spanish 

 exaggeration,' it is interesting, as well as im- 

 portant, to place beside it Humboldt's men- 

 tion, in his ' Political Essay on New Spain,' 

 p. :213 (English translation by John Black), 

 of a similar phenomenon, which took place in 

 1752. 



The whole bed of the river became dry all of a 

 sudden for more than 30 leagues above and 20 

 leagues below the Passo, and the water of the 

 river precipitated itself into a newly formed 

 chasm and only made its reappearance near the 

 Presidio de San Eleezario. This loss of the Rio 

 del Norte remained for a considerable time; the 

 fine plains which surrounded the Passo and which 

 are intersected with small canals of irrigation, 

 remained without water and the inhabitants dug 

 wells in the sand with which the bed of the river 

 was filled. At length after the lapse of several 



weeks the water resumed its ancient course, no 

 doubt because the chasm and the subterraneous 

 conductors had filled up. 



Erom this it seems fair to infer that the 

 Spaniards of 1540 were witnesses of a phe- 

 nomenon which repeated itself in 1Y52. 



Springs have also been known to be changed, 

 in that region, by earthquake shocks, and it 

 would, therefore, appear that in the past there 

 has been considerable instability in the water 

 supply. There is a probability that a large 

 branch entered the Eio Grande, from the 

 northeast, just above El-Paso, in Coronado's 

 time, which has since vanished, leaving only 

 marshy spots where it once ran. These 

 changes in volume of springs and in stream- 

 flow have, it is needless to say, an important 

 bearing on the archeology of that district. 

 E. S. Dellenbadgh. 



SPECIAL ARTICLES. 



biological SURVEY OF THE WATERS OF SOUTHERN 



CALIFORNIA BY THE MARINE LABORATORY 



OF THE UNIVERSITY OP CALIFORNIA 



AT SAN DIEGO. 



The marine biological survey undertaken 

 by the Department of Zoology of the Univer- 

 sity of California of the Pacific Ocean adja- 

 cent to the southern coasts of the state in 

 1901,* continued for six weeks in the summer 

 of 1903 at San Pedro, with a limited amount 

 of shore work and some attention to the plank- 

 ton of San Pedro harbor, and transferred in 

 the summer of 1903t to San Digeo or, more 

 specifically, to Coronado on the peninsular side 

 of the Bay of San Diego was again taken up 

 during the holiday intermission of the univer-. 

 sity for a period of three weeks from Decem- 

 ber 15, 1903, to January 6, 1904. The com- 

 mittee of the Chamber of Commerce of San 

 Diego, which raised the funds for the work of 

 the preceding summer provided also, in the 



* W. E. Ritter, ' A Summer's Dredging on the 

 Coast of Southern California,' Science, Vol. XV., 

 p. 53, 1902. 



t W. E. Ritter, ' Preliminary Report on the 

 Marine Biological Survey Work carried on by 

 the Zoological Department of the University of 

 California at San Diego,' Science, Vol. XVIII., 

 pp. 360-366, 1903. 



