426 PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES. 



most interesting objects be described and figured, and that, as far as 

 possible, the most characteristic specimens be sent home to the 

 society. Geologists who devote themselves to this investigation should 

 not neglect the rounded stones which are the detritus of rocks fre- 

 quentl}^ inaccessible. Their composition, and the fossils which they 

 contain, should form a principal object of the researches. 



7. The society, being persuaded that researches as to the origin, 

 the nature, and the increase of the deltas of great rivers are calcu- 

 lated to lead to interesting results, requests that a delta at the mouth 

 of some one of the great European rivers be exactly described; that 

 both its horizontal and vertical extent be measured; and that the 

 materials of which it consists, as well as the manner in which these 

 materials are arranged, be described and their origin determined. 

 The society desires that the description shall contain all the details 

 necessary to giving a clear idea of the form, the dimensions, the com- 

 position, and the arrangement of the materials of the delta, and an 

 accurate account of its origin. 



8. The society desires a monograph with figures of fossil birds. 



9. What are the changes which compression makes in crystals, as 

 to their qualities as conductors of heat and electricity and their re- 

 fracting power? New researches are required upon these points. 



10. When the magneto-electric apparatus is in action, heat is de- 

 veloped not only in the soft iron which alternately receives and loses 

 the magnetic state, but also, through the medium of the electric cur- 

 rent, in the helix of the conductor, and, perhaps, in other parts of the 

 apparatus. The society requests an examination, both theoretical 

 and experimental, into the relation which exists between the heat 

 developed and the motion of the various parts of the apparatus from 

 which this heat results. 



11. It is known that in Carniola and other countries animals are 

 found in grottoes where the light never enters, and where sight is a 

 useless sense. The society requests a rigid examination of at least 

 two species of these blind animals, and a clear exposition, by both 

 anatomical description and figures, of what effect is produced by 

 this blindness, especially upon the cerebral and other parts closely 

 connected with the organ of sight. 



12. Is it possible to obtain by a chemical process from certain kinds 

 of peat substances which it is impossible, or exceedingly difficult, to 

 obtain from other vegetable materials ? If this is the case, what are 

 the substances, what their chemical qualities, and what is the process? 



13. The formation of hail is by no means fully understood; we 

 require the true theory of that phenomenon founded both upon new 

 observations and upon the results of observations already known. 



14. When a compound body is traversed by an electric current it 

 frequently occurs that particles from one of the electrodes are trans- 

 ferred to the other. Endeavors have recently been made to utilize 

 this phenomenon, for the purpose of removing from the human body 

 to an exterior electrode certain deleterious matters, such as lead, 

 mercury, &c. The society requests further researches upon this sub- 



