PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES. 425 



It seems that except Professor Peirce no astroDomer has attended to 

 this important inquiry, while the correctness of the result obtained 

 by 0. Struve is strongly corroborated by his subsequent researches, 

 contributed to the ^^ Physico-31athematical Bulletin of the Academy of 

 St. Petersburg,'' vol. 9, p. 125. 



The society, consequently, desires the calculations of Professor 

 Peirce to be repeated, and also that the existing observations upon 

 Uranus and Neptune should be subjected to a strict examination, 

 with a view to determining whether the existence of Neptune can 

 be the cause of that perturbation in the motion of Uranus which 

 hitherto has not been accounted for. 



2. The comet Avhich was discovered on the 24th of July, 1852, 

 by Westphal, at Gottingen, is calculated by Sonntag and Marth to 

 describe its orbit around the sun in a period of about 60 years; a fact 

 which renders that celestial body worthy of a rigorous examination. 



The society will award its gold medal to the astronomer who, from 

 existing observations and by the most perfect method, shall deduce 

 the elements of the orbit of this comet. 



3. In order to calculate the action of the wind upon the sails of 

 vessels and windmills, and to judge of its meteorological effect, there 

 should be a thorough comprehension of the connexion between the 

 pressure exerted by the wind upon a given area and the velocity of 

 that agent. We therefore call for well-conducted experiments from 

 which there shall result an exact determination of the relation be- 

 tween the velocity of the wind and the pressure which it exerts in 

 the right lino of its direction. The society requires that the experi- 

 ments extend to a velocity of at least 20 metres per second. 



4. Experiments which were made in England by order of the 

 British government upon the resisting power of the iron employed in 

 bridges and other railroad works showed that the bars bend more 

 perceptibly under a moving than under a stationary load. The 

 society requests an analytic theory of the increase of that deflection, 

 such theory including a consideration of the w^eight of the load upon 

 the bars as well as the weight of the bars themselves; and that the 

 deflection thus theoretically ascertained be compared with the re- 

 sults of actual experiment. 



5. For some time past, and especially since so many geologists have 

 adopted the upheaval system of Elie de Beaumont, frequent attempts 

 have been made to classify the Plutonic rocks according to their 

 age. Charles d' Orbigny has recently bestowed attention upon this 

 subject, and has published a sketch, or outline, of a classification. 

 Still more recent observations have thrown so much light upon the 

 subject, that it is now possible, as regards a great number of those 

 Plutonic rocks, to determine the relative epoch of their appearance on 

 the surface of the globe. The society therefore requests a geog- 

 nostic classification of Plutonic rocks, according to the epochs of their 

 appearance as integral portions of the crust of our globe. 



6. The society requests a description and a geological chart of 

 Dutch Guiana. It is desired that especial attention be bestowed 

 upon the organic fossils to be found in that country; that the 



