Knight's cyclopædia of the industry of all nations, 1851 / [edited by George Dodd].

Date:
[1851]
Catalogue details

Licence: Public Domain Mark

Credit: Knight's cyclopædia of the industry of all nations, 1851 / [edited by George Dodd]. Source: Wellcome Collection.

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    1786 VACUUM. •VALPABAISO. 1786 V VACUUM, or VOID. In scientific enqui- ries the name vaciiim is given to space wholly- free of matter, or perfectly empty. In the common phrase, space is called empty when, so far as air can fill space, it is full of air; and even in a more scientific form of speech, there is said to he a vacuum when there is only such an approach to a vacuum as the operations of philosophy can procure. Thus in the vacuum of the air-pump, however long the attempt at exhaustion may be continued, there is always air left, though in a highly attenuated state; and even in the mercurial vacuum, or in the space which is left over the mercury of the barometer, there is not unfrequently a slight portion of air, and always an atmosphere of the vapour of mercury. Physically speaking, it is perhaps impossible to procure a vacuum: it is most likely that, even if a real vacuum could be procured for an instant, air or other vapour would at once begin to be disseminated from the sides of the vessel in which the va- cuum was made, and that the vacuum would thus instantly cease to exist. In steam machinery, the whole efficacy of the apparatus is dependent on the recurrence, at regular intervals, of a vacuum, or an ap- proximation towards a vacuum, in certam cylinders into which steam passes. [Am- Potip; Hydeaot-ics ; Steam Engine.] VALENCIA. A large proportion of this beautiful Spanish province is among the most fertile and best cultivated districts in Europe. The plain or vega of Valencia is about 30 miles long and 20 wide; the whole of this district is planted with olive, mulbeiTy, ilex, algaroba, orange, and palm-trees, and has the appearance of an immense garden. Such is the fertility of the soil that two and three crops in the year are generally obtained. The rice crops are the most valuable, and are chiefly produced in the tract which is irngated by the Albufera, a lai'ge lake in the neighboui-- hood of Valencia. The other chief product is the white mulberry, for the feeding of silk- woi-ms: the produce of silk from the vega of Valencia amounts to above one million of pounds yearly, a great part of which is ex- ported in its raw state to France. The export of fruit from Valencia is also considerable; of raisins, the quanUty exported has in some years been close upon 150,000 cwts. to Eng- land alone. The exports of barilla, almonds, figs, oil, saffron, wool, brandy, and wine, from different ports of Valencia is also very great, particularly the wine called Beni Carlo, which comes from a town of that name. Mercury, copper, sulphur, arsenic, gold, silver, lead, iron, coal, and antimony, are among the mineral products. Woollen, linen, and silken goods are made in several towns of the province, but chiefly for home consump- tion. Cordage made from the fibre of the esparto, mats, tiles, soap, glass, paper, pottery, and earthenware, are exported to all parts oi Spain. Salt is largely exported to Sweden. In the city of Valencia, the imports ai-e cod- fish, bricks, iron, coals, tobacco, colonial pro- duce, hides, manufactured goods, linen, hai-d- ware, trinkets, Norway deals, and Dutch cheese. The exports are composed of bai-iUa, wine, raisins, almonds, lead, brandy, oranges, raw silk, saffron, oil, wool, bass mats and ropes, salt, hquorice, and aniseed. The inha- bitants are chiefly devoted to agriculture, al- though many branches of trade flemish in the city. Velvets, taffetas, flowered damask, and other silk stuifs are manufactured for the home market. Woollens, camlets, hats, table- linen, gauzes, artificial flowers, potteiy, and earthenware, glass, and paper, are also made in small quantities. VALEEIAN is a herb or undershrub pos- sessing many valuable qualities. It is a native of Europe, and by the sides of rivers and in ditches and moist woods is abimdant hi Great Britain. The root has a very sti'ong smell, which is dependent on a volatile oil. It is very attractive to cats, and also to rats, and is employed by rat-catchei-s to decoy rats. It is employed also in medicine at the present day. The root, or more properly the rhizoma, with its root-fibres, is used in medicine. The medicinal action is chiefly due to the volatile oil and extractive. VALPABAISO, a large town and important seaport of Chile, is yearly rising into rank as one of the leading commercial depots on the Pacific shore of America. In 180!) only 9 vessels entered the harbour, in 1836 the number averaged 40 per month ; in 1849 the total number of foreign vessels that entered