Natural History 209 



add much to the beauty of the specimen. Different plants require 

 different degrees of pressure, according- as their texture is more or 

 less firm, and a less degree of pressure should always be used the first 

 two or three days of the process than when they approach desiccation, 

 to prevent extravasation of the juices. Succulent plants may be left 

 twelve or twenty-four 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 to 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 par- 

 tially 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 current 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 cen- 

 tral parts of thick stems, flower-buds, &c. If the oven be resorted 

 to in the earlier stages of drying, the necessary pressure will con- 

 fine the moist heated juices, and destroy the colours. I have 

 found great advantage in dry weather in placing my press close 

 to a window, opening the latter 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 ap- 

 pear 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. Mag. Nat. Hist. 

 ii. 245. 



18. Myrrh. — The following communication, respecting myrrh, 

 has been made to MM. Saigy and Raspail, editors of the Annates 

 des Sciences a" Observation, by M. Bonastre. 



I have succeeded in discovering that, in commerce, even at Paris, 

 there are two very distinct species of myrrh : the true or ancient, 

 and the false or modern ; this last is said to be brought from 



JULY— SEPT., 1829. P 



