886 IMPORTS AND EXPORTS 



These results show us that tho moan illuminating power of wax and stearine 

 candles is nearly the same. 



The illuminating power of gases and of gas-burners will bo fouud in the article 

 COAL GAS. 



ILITCEWITE. A variety of titaniferous iron ore, taking its name from one of 

 its localities the Ilmen Mountains in Siberia. 



XLVAITE. A name frequently applied to the silicate of iron, known otherwise 

 as lievrite and yenite. The term Ilvaite is derived from Ilva, tho classical name of 

 Elba one of the localities of this mineral. 



XMiviORTEliliES. Everlasting flowers, chiefly species of Ghiaphalium and other 

 Composite plants. 



XMPERMEABXiZ: is the epithet given to any kind of textile fabric rendered 

 water-proof by one or other of the following substances : 



1. Linseed-oil, to which a drying quality has been communicated by boiling with 

 litharge or sugar of lead, &c. 



2. The same oil holding in solution a little caoutchouc. 



3. A varnish made by dissolving caoutchouc in rectified petroleum or naphtha, 

 applied between two surfaces of cloth, as described under Macintosh's patent. See 

 CAOUTCHOUC. 



4. Vegetable or mineral pitch, applied hot with a brush, as in making tarpauling 

 for covering goods in ships. 



5. A solution of soap worked into cloth, and decomposed in it by the action of a 

 solution of alum ; whence results a mixture of acid, fats, and alumina, which insinuates 

 itself among all the woolly filaments, fills their interstices, and prevents the passage 

 of water. 



6. A solution of glue or isinglass, introduced into a stuff, and then acted upon by a 

 clear infusion of galls, whereby the fibres get impregnated with an insoluble, imper- 

 meable, pulverulent leather. 



7. Plaster work is rendered impermeable by mixing artificial or natural asphaltum 

 with it. 



IMPORTS AND EXPORTS. Memorandum by the Inspector-General of 

 Imports and Exports as to the method adopted for ascertaining the real value of the 

 imports into the United Kingdom, issued by the Statistical Department of the Board 

 of Trade in April 1864. 



The real value of the imports into the United Kingdom a term repeatedly employed 

 in this work as shown in the Statistical Accounts published under the authority of 

 the Government, is ascertained as follows : 



1. In the case of certain articles of those, namely, in regard to which the tariff 

 prescribes that their value (either with or without a specification of quantity) shall 

 be stated in the entry inwards at the Custom House it rests on the declaration of the 

 importers. 



If the officer of Customs to whom such declaration of value is rendered should 

 see reason to question its correctness, he is entitled to require further evidence on tho 

 point, or he may satisfy his doubts by an examination of tho goods. 



The articles of which the value is ascertained by this method, however, are but few 

 compared with the whole number of those included in the Statistical Registry, and 

 they are generally of minor importance. 



2. In tho case of the more numerous and more considerable articles which are entered 

 at the Custom House by quantity alone, the value exhibited in tho Statistical Record 

 is obtained by means of a process of computation which combines the quantity with 

 the average prices of the several commodities. 



Tho average prices thus employed are supplied to the Inspector-General of Imports 

 and Exports, in part by some of the leading merchants and brokers of the city of 

 London, who willingly aid an operation so obviously serviceable to the public ; in 

 part by three gentlemen, who have special facilities 'for watching tho course of the 

 markets, and who receive a fixed remuneration from the Treasury for collecting such 

 prices in tho ports of London, Liverpool, and Hull, respectively. 



In striking tho average price for each article, regard is had to tho specific distinc- 

 tions under which it is exhibited in tho tariff these distinctions being of necessity 

 observed also in tho Statistical Registry and not being in every instance identical 

 with those which are commonly recognised in mercantile transactions.. 



As the same article, in many cases, varies widely in its market value, according to 

 the country of which it is tho produce, separate prices, applicable to the importations 

 from the different countries, are in such cases required. 



Tho rules which are required to be kept in view in fixing the average prices will 

 appear more distinctly on reference to the annexed copy of an explanatory note which 



