( 639 ) 



bution of velocities or not. It' no attention has been paid to it, it 

 is not to be accepted that the energy always becomes tinite (see § 1); 

 if attention has been paid to it, the chance a priori can no longer 

 be taken equal for each element of volume, and the above expression 

 is faulty, and so also the furtlier reasoning. 



So it seems to me that also this derivation of Jeaxs must be 

 considered as incorrect'). 



Botany. — Some remarks on the work of Mr. A. A. Pulle, 

 entitled: "Aji enumeration of the vascular plants known from 

 Surinam, together icith their distribution and synonymy." By 

 Prof. F. A. F. C. Went. " ' . ' 



Mr. PcLLE has worked out the botanical material collected by tlie 

 expeditions of the last years, of one of which he was a member 

 himself. He has also tried to render our knowledge of the tlora of 

 Surinam more complete by incorporating into his work the older 

 collections which are preserved at Leyden, Utrecht, Göttingen, Berlin, 

 Kew Gardens and in the British Museum. 



In this way a total number of 2100 vascular plants appeared to 

 be known for Surinam and although it may be said with certainty 

 that this number is far from representing the real number of species, 

 occurring in our colony, yet we must appreciate that here for the 

 first time a comprehensive idea is given of the flora of Surinam. 



Without entering into further details it must be mentioned that 

 the author is led to the important result that phytogeographically 

 Surinam belongs to the Hylaea, the region of the Amazon river, 

 with the exception perhaps of the still unknown territory west of 

 the Wilhelmina range. The Hylaea would then extend from the 

 mouth of the Amazon river over French Guyana and Surinam and 

 gradually form a narrow littoral strip in British Guyana, finally 

 passing into the Orinoco district. As a consequence of this the 

 conception must be given up that across Surinam there is found a 

 continuous savanah district, such as occurs in Demerara and more to 

 the west; where savanahs are found in our colony their presence 

 must be entirely attributed to local intluence of the soil. 



1) Jeans' derivation occurs for the first time in the Philos. Magazine VI, 5, 1903, 

 under the title of "The Kinetic Theory of Gases developed from a New Standpoint" 

 p. 597. That also the 'molecular ungeordnef hypothesis is implied, which Jeans 

 denies, is proved by Burbcry in the same magazine VI, 6, 1903 in an article 

 on "Mr. J. H. Jeans' Theory of Gases" p. 529. 



