PARAFFINS.] 



CHEMISTRY. 



421 



remarks are from a paper by Professor Hind, of Toronto 

 University : 



"The extraordinary cheapness of petroleum, as an 

 illuminator, is too well known in Canada to require 

 any special notice. Notwithstanding the comparative 

 clearness, in this country and the United States, of the 

 chomieals (sulphuric acid and alkalies) which are required 

 to purify, deodorise, and fit it for burning in lamps, yet 

 it is, at 45 cents a gallon, incomparably the cheapest 

 illuminator which has yet been manufactured ; and it 

 threatens, for domestic purposes, to drive all other means 

 of illumination out of the field. But in Britain, France, 

 and Germany, where acid and alkalies are abundant and 

 cheap, and where various products, such as benzole, 

 tar, itc., can be utilised with profit, the preparation of 

 purified petroleum can be effected at so much cheaper 

 a rate thau on this continent, as to nearly make up the 

 difference in the cost of the raw material which freight 

 and insurance would add to it. Petroleum has arrested 

 the production of coal oil or keroline on this continent ; 

 it will soon arrest, if proper steps are taken, the produc- 

 tion of shale oil in France and Germany. " 



The following Table shows the comparative advantage 

 of this Petroleum, or Rock Oil, over all other burning 

 oils : 



PARAFFINE. We have already alluded to a substance 

 called-par.itiine, as obtained from wood-tar, and which is so 

 named n account of its weak affinity, or slight inclina- 

 ti'.n to combine with other bodies. Of late years, a 

 large quantity of paraffine and paraffine oil has been 

 obtained from Boghead coal, or Torbane-hill mineral, 

 under a patent taken out by Mr. James Young, of Bath- 

 gate, near Edinburgh. The substance whence it is pro- 

 duced has been the "chame'eon" of chemistry; for almost 

 all kinds of differing opinions have been pronounced 

 respecting it : the point to decide being, as to whether 

 it is a mineral proper, or a coal a question yet unsatis- 

 factorily determined. The following is an account of 

 Mr. Young's process : 



The raw material is hea'ed in an iron retort ; then 

 exposed to hot steam, by which the oil, tar, and paraffine 

 are volatilised. After being condensed, the product is 

 distilled, and subsequently purified by means of sul- 

 phuric acid and oxide of manganese, or bi-chromate of 

 potash. The residue having been washed, is distilled a 

 second time, and subsequently cooled, strained, and 

 ed. It is then liuated to 400 with concentrated 

 sulphuric acid ; and having been washed in hot water 

 and soda, it is afforded as a solid body, semi-transparent, 

 and presenting an appearance of bleached wax, but of a 

 more ]>t any hue. In this form it is made into candles, 

 which burn brilliantly, and without smoke. The oil 

 priuluenl from the raw material i.s employed almost 

 universally in this country in lamps, and also as a lubri- 

 cant fur machinery. 



Sine and its oil are prepared from various other 

 substances ; and lately it has been proposed to employ 

 bog-i*at in Ireland for the purpose ; but we believe that 

 the process lias not l.>-eu commercially successful. 



Hi 1 1 MKN or ASPIIALTIM ii a solid substance, obtained 

 chietly from t! 111 hood of ] 'laces abounding in 



other hydro cailx/n products. The Dead Pea has long 

 Lucu noted for its adjacent bitumen pita. This sub- 



stance is also fouud in India, America, and other places. 

 It is of a black colour, inflammable, and being easily 

 melted and moulded, is much used as a paving material 

 when mixed with sand. In this form it is employed for 

 rendering arches and railway tunnels waterproof, also as 

 a basement flooring in warehouses. 



Many substances analogous to coal, lignite, bitumen, 

 (fee. , are found in various countries ; but such are more 

 conveniently described in the sections on Mineralogy aud 

 Geology. 



VEGETABLE COLOURING MATTER. 



UNTIL within a recent period, most colours used in calico- 

 printing, paper-staining, dyeing, <fec., were chiefly ob- 

 tained from vegetable sources. Mineral dyes, however, 

 have been lately much in favour, and have the advantage, 

 where they can be used, of being lasting, and easily ap- 

 plied. Some of these thus used, and also as pigments, 

 have been described in our previous pages ; we shall, there- 

 fore, here chiefly direct attention to colours of a vegetable 

 origin. 



The natural colours of leaves and flowers are due to a 

 peculiar principle which is subject to the action of heat, 

 light, and chemical action, but which is lost on the death 

 of the plant. It is there a vital principle only. Colours 

 employed for dyeing, &C. . are extracted from tlie plant 

 after its vitality has ceased, and are resident in the leaves, 

 stems, roots, and flowers, lied dyes are obtained from 

 madder, or rubia tinctorum, safllower, or carthamus, 

 Brazil wood, logwood, sapan wood, the cochineal in- 

 sect, <tc. ; blue colours are afforded by indigo, orchil, 

 litmus, itc. ; and yellow dyes are produced from fustic, 

 turmeric, saffron, <tc. 



But all these colours per se are fugitive, and require a 

 mordnnnt to fix them in the fabrics to which they are 

 applied. The action of a mordaunt is readily illustrated 

 by that of iron and an infusion of logwood used in dye- 

 ing black. If a piece of cotton were simply dipped in the 

 infusion of logwood, it would only acquire a dirty red- 

 brown colour ; but if it be first soaked in a solution of 

 sulphate of iron, the oxide of the metal attaches itself to 

 the fibres of the material, and, on being introduced into 

 the logwood infusion, a black and permanent colour is 

 produced. The inordaunts usually employed are salts of 

 iron, alumina, aud tin, others being used only to a limited 

 extent. 



Madder is chiefly employed in dyeing red. It is the 

 root of a plant, and is imported into this country from 

 the continent in a state of powder, having a dark-red 

 colour. From it a peculiar principle, called garancine, 

 is produced by means of sulphuric acid. This prepara- 

 tion is superseding the use of the raw madder, because 

 it is more economical, cleanly, and effective. Other 

 principles maybe extracted from madder, such as pur/>ur- 

 ine, alizarine, xanthine, <fcc., of which the alizarine is 

 the most important, because it is really the colouring 

 principle of the rest, and is the chief constituent of the 

 garancine of commerce. The celebrated Turkey red dye, 

 which withstands the action of most chemical substances, 

 is obtained by means of madder. The process is long 

 and troublesome ; and we may refer our readers to a late 

 edition of Berthollet's Btcacking aiul Dycimj, for a full 

 account of all its details. 



Cochineal is properly an animal dye, but its colouring 

 powers are due to the cactus, on which it feeds. With 

 alumina, a decoction of the insect affords a rich red colour, 

 used in dyeing silk, and in producing "carmine." We 

 have succeeded in producing some rich red precipitates 

 from a cold infusion of the cactus-flower and solutions of 

 carbonate of soda and citric ncid, employed in the manner 

 we are about to describe in connection with safflower. 



Xujflower is a kind of saffron, and allb'ds two i-oloiiriii'; 

 principles a yellow and a red the former being abun- 

 dant and useless, whilst the latter is obtained only in 

 small quantities, and is very valuable as a dye for silks, 

 producing reds of the purest colour and of every shade, 

 from pink to deep poppy. 



The salilower must be washed in cold water, until all 



