24i^ Geology a7id Mineralogy, 



the juices. Succulent plants may be left exposed 12 or 24 hours (sometimes 

 several days) before pressing, to render them flaccid and more conformable; 

 and the interior parts of their stems, if bulky, and also all but the outer 

 coats of tunicated bulbs, may be removed by making a longitudinal incision 

 on the side that is to lie next the paper. On the first removal of the moist 

 paper, any irregularities in the disposition and folding of the leaves, &c., 

 may be easily rectified, as they will then be partially flattened and more 

 pliant ; and, on every subsequent removal, the plants may remain exposed 

 for half an hour or an hour on a table, and submitted to a gentle cuiTent 

 of air. This will carry off much moisture, and hasten the process ; but 

 they should be again placed under pressure when the petals begin to curl up 

 or contract. The operation of changing the papers should be repeated 

 morning and evening for the first few days, and afterwards once a day ; as 

 a general rule the oftener the better, particularly plants with purple or blue 

 flowers, from which confined moisture very soon discharges the colour. 

 After the drying is completed, it will be well to place the specimens in an 

 oven with a gentle heat and under a very slight pressure, which, in the 

 course of a night, will effectually drive off any remaining moisture that may 

 have lurked in the central parts of thick stems, flower-buds. Sec. If the 

 oven be resorted to in the earlier stages of drying, the necessary pressure 

 will confine the moist heated juices, and destroy the colours. I have found 

 great advantage in dry weather in placing my press close to a window, open- 

 ing the latter only just enough to throw a current of air round the sides of 

 the press to carry off" the moisture as it is given out. My presses are of the 

 simplest kind : flat boards, or covers of books, on which I place weights, 

 bricks, or books, to obtain the requisite pressure. Many layers of plants 

 may be put under the same press, weighting it accordingly. These details 

 may appear trifling ; but when I recollect how slowly I surmounted one 

 difficulty after another, I feel a pleasure in thinking they may be of service 

 to some of your young readers, who, like myself, at the commencement of 

 their botanical pursuits, may have no experienced friend at hand to direct 

 them. — J, E. Bowman. 



Art. IV, Geology and Mineralogy, 



Fossil Shells unpublished, — Sir, Extensive as is the catalogue of fossil 

 shells (p. 26.), it might be considerably augmented by unpublished species ; 

 and I subjoin a list which you may perhaps think worthy a place in your 

 Miscellany. My cabinet contains entire specimens of all therein enume- 

 rated, with the exception of those against which an asterisk is affixed, and of 

 which I as yet possess only imperfect specimens. I have also some other 

 fragments, but they are not perfect enough to determine the genera. 



Simple Univalves. 



