432 PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES. 



served in the height of the sea on the coasts of Holland, Belgium, and 

 France ? What changes have the currents on those coasts under- 

 gone as to their course and their velocity? And what has been 

 the effect of such changes upon the downs in Holland from the mouth 

 of the Meuse to the Helder, and upon those of the islands which lie 

 along the coasts of Friesland and Groningen, especially as to their 

 enlargement in some places and diminution in others. 



9. The character of some parts of the organs of hearing are but 

 very imperfectly known. The society calls for exact researches on this 

 subject, so that positive data may be deduced as to the functions of 

 these parts. 



10. The society calls for a monograph of the diatomes, both liv- 

 ing and fossil, of the island of Java. 



11. The application of photography might produce invaluable 

 consequences to the sublime science of astronomy if in a small 

 fraction of a second we could obtain photographic images of celes- 

 tial as we do of terrestrial bodies. Attempts have been made, but 

 with no satisfactory results, to obtain photographic images of the sun 

 and moon, the failure being especially attributable to the too great 

 length of time required for the production of these images. It seems 

 that no one hitherto has succeeded in photographing the images of 

 planets or of groups of stars. The society, with a view to making 

 photography auxiliary to astronomy, requests an exact and detailed 

 description of a photographic process by which to obtain, in a small 

 fraction of a second, good images of the celestial bodies. The author 

 of the memoir must accompany it with proofs of the process. 



12. "What, hitherto, have been the results to astronomy of the 

 numerous discoveries of small planets which revolve about the sun 

 between the orbits of Mars and Jupiter? What is their importance, 

 and what their promise as to the future? 



13. Although rheostats of different construction have rendered 

 great services to science, these instruments are still far from being 

 equal in precision of results to other scientific instruments. The so- 

 ciety, therefore, calls for the description of a rheostat free from the 

 defects of the present construction, with a succinct account of a series 

 of experiments demonstrating the superiority of the new instrument. 



14. The maximum of tension at different temperatures has, for 

 some vapors, been determined with great exactness. The Society 

 desires the same to be done for the other vapors, of which that max- 

 imum is not as yet w^ell known. 



15. Bernouilli's law as to the flow of gas does not agree with re- 

 corded experiments. The society requires new experimental re- 

 searches on this subject. 



16. Botany possesses a great many monographs which are justly 

 considered masterpieces ; we need only mention those of Richard 

 Brown, Yon Martius, Adr. de Jussieu, Grisebach, and others. 



The society desiring to promote the progress of botany in that 

 direction, will award its gold medal to the author of a good syste- 

 matic and organographic monograph of any group of plants as yet 

 but little known. 



