and the Pf/renees, in 1825. 247 



the oven, and found all that had been so long of drying, now 

 properly prepared. By this means we got rid of at least 2000 

 specimens. Indeed, we did not find more than 300 or 400 spe- 

 cimens that required farther drying, and many of these had 

 their moisture brought by the heat to the surface of the leaves, 

 so that they may probably be dried by the usual process in the 

 course of a day or two. The mode of the oven gives rise to 

 the following observations : — 1. That it must be considered a 

 good method to dry plants, (particularly in moist or cold cli- 

 mates), if proper precautions be used : 2. That for plants that 

 have been long in drying, and which have little moisture re- 

 maining, from three to six sheets of paper may be suffi- 

 cient (according to the thickness of the plants) to place be- 

 twixt each layer, and the plants need not be removed till quite 

 dry, which may be in eight or ten hours : 3. Care must be 

 taken that the oven be not too hot, otherwise the oihness (if 

 one may so call it) of the plant will be entirely extracted, and 

 it will be found quite brittle, and of little use for after exami- 

 nation : 4. If the plants be newly gathered, nine to twelve sheets 

 must at least be put between each layer of plants ; and more- 

 over, if these abound in juice (as did our Vicia narbonensis), 

 they ought to be removed from the oven when the packet (about 

 fifteen inches thick) is thoroughly heated to the centre, which 

 may be in three or four hours : the wet paper is then to be re- 

 moved, and the plants put in other which is dry ; they ought 

 then to be again baked for eight or ten hours, and will then in 

 all probability be found to be dry, unless they belong to the 

 very succulent tribes, in which case it may be preferable to fi- 

 nish the drying by the common mode : 5. All the plants put in 

 for the first time, if full of juice, should only be under a mode- 

 rate pressure, but after the paper is changed, they are to be pres- 

 sed very considerably : if they have very little moisture in them, 

 as some of the small LatJiT/ri, Polygala and Helianthema, they 

 ought at once to be subjected to a great pressure. 



" We had put in the Vicia Narbonensis fresh, and under a 

 great pressure, and we did not remove it from the oven to change 

 the paper till this morning ; the consequence was, that the paper 

 was saturated with moisture, and the specimens were stewed in 

 their own juice, and had got too much of the negro complexion. 



r2 



