302 Dr Robert E. Brown on the 



able and more comprehensive results, even in the province of 

 Geology. 



0/ the Source of Motions upon the Earth, and of the means hy 

 which they are sustained. By ROBERT E. Brown, M.D., 

 Edinburgh. Communicated by the Author. 



{Continued from fage 155.) 



Let us now take a shoi't and general survey of what has been 

 said, with the view of attempting to exhibit the conclusions to which 

 we are led, more clearly than has hitherto been done. Our atten- 

 tion has been directed chiefly to what may be termed the primary 

 forces of nature, inasmuch as all others are in some degree secondary 

 to these, being either modifications or transformations of them, or 

 derived from them, or developed in circumstances brought about by 

 their agency. These forces are, gravity, cohesion, chemical affinity, 

 and the vital and solar forces. They may be arranged in two classes 

 — the first, including cohesion, chemical affinity, and the gravity 

 of terrestrial matter ; the second, including the vital and solar forces, 

 and the gravity of external matter. These two classes of force are 

 antagonistic to each other, or at least, act 'antagonistically to each 

 other. The first class may be termed negative or conservative, be- 

 cause it tends to preserve matter in a state of aggregation and per- 

 fect rest. The second class may be termed positive or destructive, 

 because of itself it tends to produce motion, change, and ultimately, 

 perhaps, the separation and dissipation of matter. By their acting in 

 alternation to each other, therefoi'e, conservation is maintained, and, 

 at the same time, a moderate degree of motion and change is per- 

 mitted among material substances. The vital affinities and the solar 



many different sources ; but much of it is due to the officers already mentioned, 

 and to an Icelander named Gunnlogsen. 



We think it right to direct the attention of such of the German public as 

 may be interested in the geography of the north, to this beautiful and interest- 

 ing work, which is at present in course of publication. This map is divided 

 into four plates, of which the two southern are already completed ; and these 

 have afforded us important service on our journey ; while the two northern 

 ones are yet in the hands of the engravers. Major Olsen, who, with great ability 

 and untiring diligence, sujJerintends the topograjjhical works in the kingdom 

 of Denmark, has pevseveringly laboured, from time to time, to amend and to 

 perfect the details of his Icelandic chart, so far as the scale permits, according 

 to all new information of a trustworthy kind. Thus, of this inhospitable and 

 almost desolate country, we possess a much better map than we do of the Island 

 of Sicily.. 



