1820.] Harlem Philosophical Society. 465 



out contagion? In this case, are the precautions used in neigh- 

 bourincr countries to prevent such contagion sufficient to produce 

 Derfecfsecurity? or if there still remain any apprehension, what 

 should be still done to prevent as much as possible the conta- 

 gion from spreading ? " , • i • • i ui, 

 6 " How far are we acquainted on chemical prmciples with 

 the processes employed in brewing diffei;ent kinds of beer ; and 

 what information does our actual knowledge on this point supply 

 us with that may tend either to improve such hquors, or render 



them more profitable ? " j i. u <. 



• 7 " What does experience teach us with regard to what 

 ouo-iit to be observed in the multiplication and culture of new 

 varieties of fruit trees by means of seeds in order to prevent the 

 diminution of the good qualities of the varieties that have been 

 obtained, and their entire annihilation?;' 



8 ''■ In what consists the difference m the constitution ot the 

 atmosphere in those parts of the Netherlands which vary most 

 in point of situation, and what are the diseases which are aftected 

 by this different disposition ? " x- i, • i, v„\.^ 



9 " Is there any plan by the adoption of which gas light 

 misht be advantageously employed in private families .' 



10 " What sure and practicable methods can be derived from 

 the present state of physical and chemical knowledge to prevent 

 or arrest endemic maladies, occasioned by the draining of exten- 

 sive lakes or by exhalations arising from the bottoms of lakes 



that have been drained ? " • t e a 



11 " What salutary or pernicious alterations does food sus- 

 tain from the action of fire ; and what rules can hence be derived 

 for producing such modifications as may render aliment most 

 nutritious and wholesome ?" 



19 " How far are we acquainted with the properties ot that 

 species of fungi, which grows beneath planks of wood, causing 

 them to decay? Are there any means to be hence suggested 

 either for its prevention or extirpation, or at least a diminution ot 



its pernicious effects ? " 



13 " What is the peculiar nature of the green matter appear- 

 ino- on the surface of stagnant water in calm and warm weather, 

 particularly during July and August, and known under the 

 name of tiyssas Flos aqucz ? Is there reason to regard it, accord- 

 ing to the general opinion, as a cryptogamous plant, or is it ot an 

 animal nature? Is it an inorganic production originaung in a 

 chemical union of certain principles when the degree of tempe^ 

 ature and other circumstances are favourable ? What wU che- 

 mical analysis be able to prove? Is there any method of 

 preventing the production of this matter in water, or of causing 

 ft to disappear? Is the water covered with this matter, and pro- 

 ducincr a disagreeable effluvia injurious to health . 



14. " It is demanded that a complete and succinct system be 



Vol. XVI. N° VI. 2 G 



