440 PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES. 



sists of two distinct parts — the spark, properly so called, and a lu- 

 minous aureola. New researches are required upon the causes of 

 this division, and the phenomena which accompany it, and upon the 

 different qualities of the two parts of the same luminous discharge. 



19. The experiments of M. Quincke have demonstrated that the 

 forced passage of a liquid across a porous diaphragm developes an 

 electric current. New researches are demanded which may make 

 known the cause of this remarkable phenomenon. 



20. The society desires soundings to be taken in various seas for 

 the purpose of procuring specimens of the beds. The specimens 

 thus procured are to be carefully examined with a view to discovering 

 whatever there is that is interesting in these submarine deposits. 



21. Exact researches are requested upon the transparency of the 

 atmosphere of Java as compared with that of some European country. 



22. In the mountainous country of the left bank of the Rhine, 

 known by the name of Ejjfiel, there are several conical mountains 

 which evidently owe their existence to volcanic action. The society 

 requests it to be determined, by exact observations made upon the 

 spot, whether there exists traces of upheaval of the older strata, or 

 whether those mountains are not cones of eruption. 



The question relating to the fossils of Oeningen, from which the 

 society has been so fortunate as to induce the production of crowned 

 memoirs upon the lishes and the insects, still remains open to com- 

 petitors as regards the mamniifers and the reptiles. 



The usual prize for a satisfactory reply to each of the questions is a 

 gold medal of the value of 150 florins, and, when the reply is deemed 

 worthy, an additional premium of 150 Dutch florins in money. Re- 

 plies very legibly written in Dutch, French, English, Italian, or Ger- 

 man, (in the Roman character,) and post paid ^ with sealed notes in the 

 usual way, must be addressed to M. J. G. S. Breda, perpetual secre- 

 tary of the society, Harlem. 



EXTRACT FROM THE PROCEEDINGS OF THE HOLLAND SOCIETY OF SCIENCES, 

 AT HARLEM, FOR THE TEAR 1862. 



The society held its llOth annual session May 17, 1862. Since its 

 last general session no satisfactory response has been received to the 

 C]uestions which it had offered for competition. 



Dr. P. Bleeker, a member of the society, has sent ?^, Memoir intended 

 as a contribution to tlie natural liistory of tlie fish of the coast of Guinea; 

 and Drs. F. J. S. Schmidt, G. S. Godhart, and J. Van der Hoeven 

 have transmitted a Blemoir on tlie anatomy of tlie Cryptohranchus Ja- 

 2?onicus. By the unanimous recommendation of the members con- 

 sulted these two works will form a part of the memoirs of the society. 



The society has thought proper to repeat the following questions, 



