General View of the Coal Mines worked in France. 15 



"because it has lived there : 2d, That if the leaves of the ne- 

 nuphar have pores on their superior surface and not on the 

 inferior, it is because the former is intended to exist in the 

 air, and the other in the water. 



I shall here add, tliat the leaves of the nenuphar are pro- 

 vided with pores in the upper surface before tJiey reach the 

 surface of the water ; and I have observed that the lower 

 surface of the same leaves had not acquired pores, though 

 they vegetated a long time in the air, in consequence of the 

 desiccation of marshes ; which proves that the contact of the 

 air has no influence in the formation of pores which arc 

 seen on vegetables destined to be provided with them. 



We are told by C. DccandoUe, that having caused mint 

 to vegetate under water, it shot furtli leaves destitute of 

 pores. To this observation I shall oppose one which I 

 made on the leaves of the narcissus, which after having 

 shot forth in water were furnished with as many pores aS if 

 they had vegetated in the open air, as I had reason naturally 

 to expect, since the leaves, still contained in the bulb, ex- 

 hibited to me their pores already completely formed. 



It appeals then that the existence of pores does not de- 

 pend either on the light or the air; but that these organs are 

 co-existent with the other parts of the vegetable. 



[To be continutd.] 



II. A general View of the Coal Mines worked in France, 

 of their different Products, and the Means of circulating 

 them. By C. Lefebvre, Member of the Council of 

 Mines, of the Philomatic Society, &c. ^c. 



^Continued from vol. xv. ; . 3+5.] 



Department of Oise. 



JlNothino has hitherto been found in this department but 

 very abundant strata of highly pyritous peat. Such are 

 those in the commune of Beaurain, Guiscart, and Muyrau- 

 court, Fretoy, and several other places in the environs of 

 Xoyon. This peat can be considered only as a bad kind 

 of fuel. By subjecting it to proper treatment, to de- 

 compose the pyrites, sulphate of iron (green copperas) and 

 even sulphate of alumine (common alum) may be ob- 

 tained from it. It is susceptible of spontaneous inflam- 

 mation when exposed to the air in masses. It is much 

 employed for manure, either before or after incineration. 



Department 



