July 14, 1905.] 



SCIENCE. 



5T 



type is the result of a long struggle for ex- 

 istence between different species, in which 

 only those possessing the greatest vitality and 

 best fitted to the physical conditions of situa- 

 tion succeed in occupying the ground and form 

 tree associations having a distinct physi- 

 ognomy. One of the most important char- 

 acteristics of a forest type is its stability, 

 its resistance to invasion by other plant 

 forms. * * * " 



TEE FOSSIL ARACHNIDA OF BOHEMIA. 



We are indebted to Professor Dr. Anton 

 Fritsch for another important contribution on 

 the Permian and Cretaceous fauna of Bohemia 

 entitled ' ISTeue Pische und Eeptilien.' This 

 takes the form of a quarto appendix to his pre- 

 viously published volumes, and is illustrated 

 by nine plates. The Cretaceous forms de- 

 scribed are new teleosts, plesiosaurs, mosasaurs 

 and pterosaurs. 



In 1904 there appeared from the pen and 

 brush of this ardent paleontologist a fine mono- 

 graph on the Paleozoic arachnida, consisting 

 of eighty pages of text and fifteen plates. The 

 conclusions reached in this monograph are 

 most striking, especially as to the very great 

 antiquity of modern forms. The author ob- 

 serves " If we examine the entire series of the 

 forms described we must recognize that there 

 are many which present no very striking differ- 

 ences from the Arachnida of to-day. They are 

 to be regarded as the direct ancestors of 

 families now existing in part as lateral 

 branches which have later become extinct." 

 This is true of members of six families de- 

 scribed. The scorpions of the Silurian period 

 show in their foot structure a primitive form 

 suggesting that of the Crustacea whereas those 

 of the Carboniferous and Permian formations 

 exhibit close resemblance to the foot structure 

 of the modern types. 



H. F. O. 



EXTENDED EXPLORATIONS OF THE 



ATMOSPHERE BY THE BLUE HILL 



OBSERVATORY. 



Accounts of the first experiments in this 

 country with hallons-sondes, for the purpose 

 of ascertaining the meteorological conditions 



at great heights above the American continent, 

 appeared in Science, Vol. XXL, pp. Y6-7Y and 

 335. DiTring the months of January, Febru- 

 ary and March, 1905, nine more ascents were 

 made from St. Louis and every balloon but one 

 was found and, with the attached instrument, 

 was returned to Blue Hill in accordance with 

 the instructions on each. Like the previous 

 balloons, all of these fell within the eastern 

 half of a circle having its center at St. Louis 

 and a radius of 285 miles. The German ex- 

 panding rubber-balloons, filled with hydro- 

 gen generated by the vitriolic process, were 

 again employed, as were the French self-record- 

 ing instruments, which gave at least partial 

 records of barometric pressure and air-tem- 

 perature in seven of the nine ascensions^ 

 although another record was obliterated by the 

 finder. On January 25, when a high baro- 

 metric pressure prevailed at the ground, a 

 temperature of — 111° F. was recorded at the 

 height of 48,700 feet, this being one of the 

 lowest natural temperatures ever observed. The 

 experiments last winter were conducted by Mr. 

 Clayton, under the direction of Mr. Rotch, 

 and their success induced Professor Langley, 

 secretary of the Smithsonian Institution, to 

 grant Mr. Rotch $1,000 from the Hodgkins 

 Fund, in order to continue the experiments 

 this summer at St. Louis. These, like the 

 first, will be conducted by Mr. Fergusson, of 

 the Blue Hill Observatory staff. Soundings 

 of the atmosphere made at different seasons 

 should reveal the annual variation of temper- 

 ature at great heights above the American con- 

 tinent, which is at present unknown. 



However, kites are not neglected at Blue 

 Hill, for, besides the flights made there each 

 month on the days fixed by an international 

 committee, they are also being employed to 

 ascertain the conditions above the Atlantic 

 Ocean in the trade-wind region. Thus the in- 

 vestigation which was first proposed by Mr. 

 Rotch in Science, Vol. XIV., pp. 412-413, 

 and which has been persistently advocated by 

 him since, is now in progress, and this was 

 rendered possible through the cooperation of 

 the well-known French meteorologist, M. L. 

 Teisserenc de Bort, who' placed his steam- 

 yacht at the disposal of Mr. Rotch, on condi- 



