566 



HISTORY OF THE VEGETABLE KINGDOM. 



This sulstance is, however, furnished by other 

 trees, as ; escemcaria, agalloclio, hippomane, mana- 

 nella, hura crepitans, sapium aucuparium, plu- 

 kenetia wluhilis, jatrophas maheea, and ompha- 

 leus. 



This substance was little known in Europe 

 till the voyage of M. Condamine, in 1760, into 

 the interior of South America, where he exam- 

 ined the tree; and on his return laid a descrip- 

 tion of it, and the manner of preparing the gum, 

 before the French Academy. The mode in which 

 the juice is obtained by the natives, is by mak- 

 ing incisions through the bark of the lower part 

 of the trunk of the tree, from which the fluid 

 resin issues in great abundance, appearing of a 

 milky whiteness as it flows into the vessel placed 

 to receive it, and into which it is conducted by 

 means of a tube or leaf^ fixed in the incisions, 

 and supported with clay. On exposure to the 

 air, this milky juice gradually thickens into a 

 soft, reddish, elastic resin. To suit the different 

 purposes for which it is employed in South 

 America, the caoutchouc is shaped into different 

 fonns; but it is commonly brought to Europe 

 in that of pear-shaped bottles, which are said to 

 be formed by spreading the juice of the siphonia 

 over a proper mould of clay, and as soon as one 

 layer is dry another is added, till the bottle be 

 of the thickness desired. It is then exposed to 

 a dense smoke, or to a fire, until it becomes 

 so dry as not to stick to the fingers, when, by 

 means of certain instruments of iron or wood, 

 it is ornamented on the outside with various 

 figures. This being done, it remains only to 

 pick out the moulds, which is easily effected on 

 their being first softened with water. 



Caoutchouc is insoluble, and consequently 

 impervious to water, alcohol, and most fluids. 

 Some of the essential oils dissolve it; but its 

 elasticity and other properties are thereby lost. 

 Two solvents have been discovered for it, ether 

 and naphtha, or essential oil of tar. The natives 

 of South America have long been in the habit 

 of using this juice for a variety of purposes. 

 They collect it chiefly in the rainy season, 

 because, though it exudes at aU times, it flows 

 then most abundantly. The inhabitants of 

 Quito prepare a kind of cloth of it, which they 

 apply to the same purposes as the Mackintosh 

 fabrics, so common now in this country. 



They also form it into flambeaux, which give 

 a beautiful light, and emit an odour which is 

 not unpleasant to those who are accustomed to 

 use them; but Europeans are annoyed by the 

 foetid smell which they diffuse. One of them 

 an inch and a half in diameter, and two feet 

 long, will bum during twelve hours. 



Tliough not used directly in medicine, caout- 

 chouc is found of essential service for the con- 

 sti-uction of several medical instruments, for 

 which its softness, pliancy, and its power of 



resisting the various fluids of the body, renders 

 it extremely appropriate. 



CHAP. LII. 



GARDEN FLOWERS — HYACINTH, TULIP, &C. 



We have hitherto treated of vegetables useful 

 to man, it remains to consider those which are 

 peculiarly adapted for ornament. Almost every 

 vegetable production has an aspect of beauty, 

 and no ornaments can exceed those which the 

 generality of flowering plants possess. Whether 

 we consider the splendour, variety, and delicacy 

 of their colour, the symmetry and minute detail 

 of their proportions ; the gracefulness of single 

 simple form, or the gorgeous luxuriance of their 

 gTOuped masses. If to this we add the delicious 

 odour which they constantly and spontaneously 

 diffuse, we need not wonder that flowers should 

 be universal favourites, and that we should find 

 them ornamenting the humblest cottage as well 

 as the proudest palace. 



By long and judicious cultivation, garden 

 flowers undergo as remarkable changes as take 

 place so strikingly in culinary vegetables. They 

 increase in size, in depth, and variety of colour, 

 and even change their forms. One of the 

 most remarkable changes is that of their becom- 

 ing what is called double. That is, the number 

 of petals of the corolla increase many fold, as in 

 the rose, and anemone, while the stamens and 

 pistils, or organs of fructification, become almost 

 or entirely obliterated, or converted into petals. 

 To many tastes, perhaps, the simple and appro- 

 priate forms of the native flowers are more 

 beautiful than this artificial monstrosity, yet it 

 cannot be denied, but that the tints and lux- 

 uriant aspect of many flowers are decidedly 

 improved by cultivation. Hence has arisen an 

 artificial standard, among florists, of judging of 

 flowers, which has been called the "canons of 

 criticism." As suited for every day domestic 

 ornaments, flower gardens, or plots, or borders, 

 should be situated near the house, so as easy 

 access may be obtained to them, or if not closel}- 

 adjoining to the house, they may be placed so 

 as to be seen from the windows. A south 

 situation, or one inclining to the south-west, 

 south-east, or east, is most desirable. When the 

 space is limited, horizontal or gentle sloping 

 borders will be found most convenient, while on 

 the other hand, if the grounds are more exten- 

 sive, a waved irregular surface will afford the 

 greatest scope for taste in an-angement. The 

 surface should be rather elevated, not low, 

 sufficiently sheltered from the winds, yet open 

 and free to the sun, not overshadowed or covered 

 with trees, or otlier higli foliage. A few elegant 



