556 
VANDA. 
acids; and unites, in its proper capacity of an 
acid, with salifiable bases, often in two or more 
proportions, forming soluble salts with the alka- 
lies, and in general sparingly soluble salts with 
the other metallic oxides. 
VANDA. A genus of ornamental, tropical 
plants, of the orchis family. Hight or nine spe- 
cies, chiefly epiphytes, varying in height from 8 
to 25 inches, were introduced to Britain, princi- 
pally from China, within the first 35 years of the 
present century. Three of the most handsome 
are the many-flowered, V. multiflora, two feet 
high, carrying yellow flowers in June; the taper- 
leaved, V. teres, two feet high, carrying pale yellow 
flowers in June; and Roxburgh’s, V. Roxburghi, 
18 inches high, carrying white and purple flowers 
in November, and comprising one variety with 
whole colour, and another with tesselated sepals 
and petals. See the article Oncuis. 
VANGUIERA. A genus of curious, exotic, 
evergreen shrubs, of the madder family. The 
eatable species, V. edulis, is a native of India, 
and was introduced thence about 40 years ago to 
the botanical collections of Britain. It ranks, in 
the estimation of the Hindoos, as a fruit shrub; 
and it has naturally a height of between 12 and 
20 feet. Two species, 3 or 4 feet high, have been 
introduced from Madagascar. 
VANILLA. A genus of ornamental, economi- 
cal, tropical plants of the orchis family. Two 
climbing species, the smooth-leaved and the aro- 
matic,—and one epiphytous species, the two- 
coloured,—have been introduced to British hot- 
houses from tropical America; and all, inclusive 
of a number of varieties, are remarkable for the 
fragrance of their fruit or pods, but cannot, 
without difficulty, be made to thrive and still 
less to fructify under artificial European culture. 
The fruit of the most common varieties has long 
been assiduously gathered in their native re- 
gions, and exported thence to Britain and other 
countries, as an esteemed ingredient for flavour- 
ing or perfuming ices, creams, chocolate, snuff, 
hair-oils, fine unguents, and other preparations. 
“The plant which produces the fruit called va- 
nilla,” says Miller, “hath a trailing stem, some- 
what like common ivy, but not so woody, which 
fastens itself to whatever tree grows near it, by 
small fibres or roots which are produced at every 
joint, which fasten to the bark of the tree, and 
by which the plants are often nourished when 
they are cut or broken off from the root, a con- 
siderable height from the ground, in like man- 
ner as the ivy is often seen in England. The 
leaves are as large as those of the common lau- 
rel, but are not quite so thick. These are pro- 
duced alternately at every joint, which are 6 or 
7 inches asunder, and are of a lively green colour 
on the upper side, but of a paler green under- 
neath. The stems of these plants shoot into 
many branches, which fasten themselves also to 
the branches of the trees, by which means they 
rise 18 or 20 feet high, and spread quite over 
VAPOUR. 
some of the smaller trees to which they are 
joined. The flowers are of a greenish yellow 
colour, mixed with white, which, when fallen, 
are succeeded by the fruit, which are 6 or 7 
inches long. The method used to prepare the 
fruit, is, when it turns of a yellow colour, and 
begins to open, to gather it, and lay it in small 
heaps to ferment two or three days, in the same 
manner as is practised for the cocoa or chocolate 
pods; then they spread them in the sun to dry, 
and when they are about half dried, they flat. 
them with their hands, and afterwards rub them 
over with the oil of palma christi, or of the 
cocoa; then they expose them to the sun again 
to dry, and afterward they rub them over with 
oil a second time; then they put them in small 
bundles, covering them with the leaves of the 
Indian reed, to preserve them. These plants 
produce but one crop of fruit in a year, which is 
commonly ripe in May, fit for gathering; for 
they do not let them remain on the plants to 
be perfectly mature, because then they are not 
so fit for use. While the fruit is green, it affords 
no remarkable scent; but as it ripens, it emits a 
most grateful aromatic odour. When the fruit 
begins to open, the birds attack them and devour 
all the seeds very greedily, but do not eat any 
other part of the fruit. The fruit which are 
brought to Europe, are of a dark brown colour, 
about 6 inches long, and scarce an inch broad; 
they are wrinkled on the outside, and full of a 
vast number of black seeds, like grains of sands, 
of a pleasant smell, like balsam of Peru.” The 
best kind to experiment with in British gardens 
is V. planifolia,—a climber introduced from the 
West Indies in 1800; and any attempt to bring 
it to fruit must be aided by artificial fecunda- 
tion; and this is done by carefully removing the 
retinaculum which covers the stigmatic part of 
the column, and then drawing out the inward- 
turned anther and pushing it down till it comes 
in contact with the bearded stigmatic part. By 
this management fruit have recently been ob- 
tained in British hothouses as finely fragrant as 
any which are imported from Mexico. 
VAPOUR. A body in such an aeriform state 
as, while for the time truly gaseous, has a readi- 
ness to return to the liquid or the solid state at 
or above ordinary temperature and pressure. See 
the article Anrirorm Bopirns. Vaporization, or 
the conversion of a liquid or a solid into vapour, 
is effected by heat; and takes place either slowly 
and quietly in evaporation, or rapidly and tu- 
multuously in ebullition. See the articles Eva- 
PORATION and Bortine. A considerable number 
of substances will not vaporize under the strong- 
est heat of our furnaces; a few, such as arsenic, 
camphor, and sal-ammoniac, pass direct from 
the solid state into vapour ; and the great majo- 
rity are first liquefied and then vaporized, and 
differ very widely from one another as to the 
degree of heat by which their vaporization is 
effected, and as to the comparative density 
