1008 



SCIENCE. 



[N. S. Vol. XVII. No. 443. 



of fuller's earth. Quartz sand and amorphous 

 silica exhibit practically no selective action. 

 Powdered limestone was equally inefPective. 

 Different clays show greatly differing capacity 

 for separating the petroleum oils, the greatest 

 effectiveness being secured as the clay ap- 

 proaches fuller's earth in composition and 

 texture. 



Interesting practical and scientific sugges- 

 tions made by Dr. Day as a result of his ex- 

 periments were, first, that the great variety 

 in color, specific gravity, viscosity, etc., of the 

 different Pennsylvania oils may be due to dif- 

 ferences in amount of diffusion suffered by 

 these oils in passing upward through Carbon- 

 iferous shales from a common source, rather 

 than to differences in original composition; 

 and a corollary of this suggestion is that these 

 oils and those of the Trenton district in west- 

 ern Ohio may have an identical original source 

 far down in the geologic column, the present 

 differences being due to the greater diffusion 

 suffered by the Pennsylvania oils in passing 

 upward through the intervening strata to the 

 horizons in which they are now found. 



An examination of the Texas oils shows 

 that they contain considerable amounts of 

 constituents which are most easily removed by 

 diffusion, the conclusion being, therefore, that 

 they are nearer the original source than the 

 Ohio and Pennsylvania oils. 



At the conclusion of Dr. Day's paper a 

 number of geologists, among them Messrs. 

 Hill, Eldridge, Hayes, Adams, Butts and 

 Fuller, disciissed various phases of the prob- 

 lem of the origin and storage of the fluid and 

 gaseous hydrocarbons, the suggestions of Dr. 

 Day as to the competency of fractional dis- 

 tillation by diffusion to account for the pres- 

 ent differences in native oils, and the further 

 suggestions of a common origin for many of 

 them being regarded as of particular interest. 

 W. C. Mendenhall, 



Secretary. 



DISCUSSION AND C0BBE8P0NDEN0E. 



THE PROPOSED BIOLOGICAL LABORATORY AT THE 

 TORTUGAS. 



To THE Editor of Science: Since the sub- 

 ject of a research laboratory in or near the 



tropics is under discussion, I would like to 

 have the privilege of a few comments. For 

 the last two years I have been discussing the 

 matter privately with a number of people who 

 are interested in establishing a subtropical 

 biological laboratory. This is by no means 

 new, since an attempt was made a few years 

 ago to carry on research work at Bimini, an 

 island about fifty miles east of Miami. At 

 another time the question of locating a labo- 

 ratory at Miami was under discussion, and 

 my department (biology) at the Florida Agri- 

 cultural College pledged a small sum to aid 

 in the expense of carrying on this work. 



The advantages of establishing such a labo- 

 ratory at Miami may be stated as follows : (1) 

 Miami is about one degree of latitude south 

 of the northern limits of the Antillean flora. 

 (2) The city is located on the Biscayne Bay, 

 a magnificent sheet of water that is always 

 navigable to sail-boats and launches. (3) The 

 Gulf Stream is within easy reach, being only 

 about six or seVen miles out, cat-boats and 

 launches making one or two trips a day dur- 

 ing the tourist season. (4) The Miami River, 

 Little River and other streams, which drain 

 the everglades, may be explored easily for 

 fresh-water forms. (5) The everglades can 

 be reached by row-boat or bicycle, macadam- 

 ized roads having been built to the edge of 

 the glades. This vast unexplored region, 

 about which so many erroneous ideas are 

 abroad, is now open for botanical exploration. 

 (6) Miami is within twenty-four hours of 

 Havana and twelve hours of Key West by 

 steamer. Washington can be reached in 

 thirty-six hours. (7) Launches and sail- 

 boats may be chartered at any time at reason- 

 able rates. (8) Miami is located south of 

 the 26th degree of north latitude. 



At the present time the tropical laboratory 

 has only one room which can be offered to 

 visiting biologists. This has been in almost 

 constant use during the past year. Among 

 those who have taken advantage of this op- 

 portunity are Professors V. M. Spalding and 

 J. H. Comstock. 



There can be no doubt as to the healthful- 

 ness of the location, and the comforts of life 



