Dutch Society of Science of Haarlem. 151 



which has especially been proved by Faraday's experiments ; and as it follows 

 that the division of bodies, according to their form, into liquids and gases, has 

 become uncertain and less admissible, the society asks, 1st, In how fer may the 

 classification of bodies, according'to form, be yet admitted ? 2d, What are the 

 truly gaseous and vaporous bodies ? What use might be made in the arts of 

 those substances, which, when they are strongly compressed or cooled, are 

 capable of exercising a great degree of power by elasticity or dilatation ? 



Although the following questions, proposed to be answered before Ist Ja- 

 nuary 1829, be too late of insertion, the perusal of them may prove inte- 

 resting : — 



What is the present state of our knowledge respecting the motion of the 

 juices of plants? What are the observations and experiments which throw 

 some light on the cause of this motion, and on the vessels or organs by which 

 it takes place ? What may be considered as sufficiently proved, by well ve- 

 rified exjjeriraents, of all that natural philosophers have written on this sub- 

 ject ? What is there that may be considered as not yet sufficiently proved 

 or merely hypothetical ? And what use may be derived from the knowledge 

 acquired in respect to this subject for the culture of plants ? 



The theory by which it is supposed that all the chemical actions of bodies 

 are the effect of electricity being more and more adopted, there is asked, — A 

 critical examination of all that experiment has proved on this subject, in or- 

 der that we may be able to conclude from it, whether electricity alone ought 

 to be considered as the cause of all chemical action, or if it be still necessary 

 to suppose a particular power known under the name of chemical affinity. 



What are, since the publication of M. Decandolle's " Essai sur les Propri^- 

 t^ Medicales des Plantes, compar6es avec leurs Formes Exterieures et leur 

 Classification Naturelle," (3d edit. Paris, 1816), the observations and experi- 

 ments by which the theory exposed in that work may be confirmed and illus- 

 trated ? What are the exceptions and contradictions which remain to be re- 

 solved with respect to that theory ? 



The coniferous trees differing considerably from other trees in their struc- 

 ture and mode of growth, as well as in the peculiar matters which they con- 

 tain, and in ether properties, there is desired — An exact comparison of tlic 

 structure of the coniferous trees with that of other trees, and that, by ulterior 

 researches, it be tried to demonstrate in what degree this difference of struc- 

 ture may serve, whether to explain the other properties of coniferous trees, or 

 to deduce useful precepts for the cultivation of these trees. 



In what manner do peat-ashes augment the fertility of some soils, while it 

 is known to contain very little of those principles which chiefly serve as ali- 

 ment to plants ? Of what qualities are these soils, of which it is known by 

 experiment that their fertility may be augmented by peat-ashes ? To what 

 soils are they injurious ? What useful indications may be deduced from what 

 will be said in reply to the two first parts of this question ? 



What is the origin of the blocks of granitic and other primitive rocks, which 

 are met with of different dimensions, and in very great abundance, dissemi- 

 nated in the plains, and in some sandy deposits of the kingdom of the Low 

 Country and of the north of Germany ? Is it possible to be assured, by an 

 exact comparison of these blocks of granite, and of the pebbles of the sandy 



