(If r. MISTRY. 



emit* au agreeable aromatic odour. Water docs not act 

 upon it. Alcohol, when hot, dittolrrt one tenth of iti 

 weight, but let* most of it fall again on cooling. Hot 

 dissolves about one-fourth of it* weight ; and 

 when (lowly cooled, dcpositca it in crytt.dline plate*, 

 like spermaceti. The ether acquire* a green colour, but 

 the wax become* nearly white. Oil of turpentine, when 

 assisted by heat, dissolve* it sparingly. Alkalu-s act 

 upon it nearly u on beet wax. The same remark ap- 

 plies to acid*. Sulphuric acid, when assisted by heat, 

 dissolve* about one-twelfth of its weight, and U convert- 

 ed into a thick dark brown mass. 



The Chinese extract a wax from various vegetables, 

 which they manufacture into candles, and of which they 

 form many delicate ornaments which are brought to 

 Europe. 



SECT. XXI. Camphor. 



Camphor. The substance called camphor, though unknown to 

 the Greeks and Romans, seems to have been long known 

 in the East. When it was first brought to Europe does 

 not appear, though it seems to have been introduced by 

 the Arabians. 



1*w ob- i t C omes to Europe chiefly from Japan. It is ob- 



tained from the laurus cainphora, a tree common in the 

 East, by distilling the wood along with water in large 

 iron pots, on which are fitted earthen heads stuffed with 

 straw. The camphor sublimes, and concretes upon the 

 straw in the form of a grey powder. It is afterwards 

 refined in Holland by a second sublimation. The ves- 

 sel* are of glass, and somewhat of the bliape of a tur- 

 nip, with a small mouth above loosely covered with pa. 

 per. According to Ferber, about one-fourth of pound* 

 ed chalk is mixed with crude camphor ; but others as- 

 sure us that there is no addition whatever employed. 

 In proper. Camphor thus confined is a white brittle substance, 

 lies. having a peculiar aromatic odour, and a strong hot acrid 



taste. Its specific gravity is 0.9887. 



It is not altered by atmospheric air ; but it is so vo- 

 latile, that if it be exposed during warm weather in an 

 open vessel, it evaporates completely. When sublimed 

 in close vessels it crystallizes in hexagonal plates or py- 

 ramids. 



It is insoluble in water ; but it communicates to that 

 liquid a certain portion of its peculiar odour. 



It dissolves readily in alcohol, and is precipitated again 

 by water. According to Neumann, well rectified alco- 

 hol dissolves three fourths of its weight of camphor. By 

 distillation the alcohol passes over first, and leaves the 

 camphor. This property affords an easy method of pu- 

 rifying camphor. Dissolve the camphor in alcohol, dis- 

 til off the spirit, and melt the camphor into a cake in a 

 glass vessel. 



Camphor is soluble alto in oils, both fixed and volatile. 

 If the solution be made by mean* of heat, as it cools 

 part of the camphor precipitates, and assumes the form 

 of plumose or feather-like crystals. 



Camphor is not acted on by alkalies, either pure or iu 

 the state of carbonate*. Pure alkalies, indeed, seem to 

 dissolve a little camphor ; but the quantity is too small 

 to be perceptible by any other quality than its odour. 

 Neither is it acted on by any of the neutral salts which 

 have hitherto been tried. 



Acids dissolve camphor without effervescence, and in 

 general it may be precipitated unaltered from the recent 

 solution. 



When heat is applied to camphor it is volatilized. If 

 the heat be tuddcn and strong, the camphor melts before 

 * 





it evaporates ; and it melt*, according to Ventiui, at the 

 temperature of 300* ; accon! mien, at ' 



It catches fire very readily, and emit* a great tl 

 flame a* it burns, but it leaves no residuum. It is so in- ^' 

 flammable that it continues to burn even on the si.- 

 of water. When camphor is et on fire in a large glass 

 globe, filled with oxygen ^as, and containing a little water, 

 it burns with a very bright flame, and produces a great 

 deal of heat. The inner surface of the glass is toon co- 

 vered with a black powder, which has afi the properties 

 of charcoal ; a quantity of carbonic acid gas is evolved ; 

 the water in the globe acquires a strong smell, and it im- 

 pregnated with carbonic acid and camphoric acid. 



There are several species of camphor which have been DilTerent 

 examined by chemists, and which differ considerably from ipccies of 

 each other in their properties. The most remarkable are camjil.ur. 

 common camphor, the camphor nf volatile oils, and the 

 camphor obtained by treating oil of turpentine with mu- 

 riatic acid. 



Common camphor, obtained by distillation from the 

 Inurus camphora, is the substance which has been de- 

 scribed in the preceding part of this Chapter. In Bor- 

 neo and Sumatra campnor it procured from the liinnts 

 siimalreiifis ; but as none of this camphor is brought, 

 to Europe, we do not know how far it agrees with com. 

 mon camphor in its properties The latirus ciiinamonmm 

 likewise yields camphor. 



The second species of camphor seems to exist in a 

 great variety of plants, and is held in solution by the vo- 

 latile oils extracted from them. Neumann obtained it 

 from oil* of thyme, marjoram, cardomum ; Hermann, 

 from oils extracted from various species of mint. Car- 

 theuser obtained it from the roots of the tnt: ifi, 



ka-mjil'i-rin rotunda, aiitomtim xuizi/>er, laurus ctisnia, and 

 rendered it probable that it is contained in almost all the 

 labiatvd plants. It ha* been supposed to exist in : 

 plants combined with volatile oil. Proust has shown 

 how it may be extracted, in considerable quantity, from 

 many volatile oils. 



From the observations of Mr John Brown, there is 

 reason to believe that the camphor from oil of thyme dif- 

 fers from common camphor in several respects. It doe? 

 not appear to fcrm a liquid solution either with nitric or 

 sulphuric acid j nor is it precipitated from nitric acid in 

 powder like common camphor, but in a glutinous mass. 



The artificial camphor yielded by oil of turpentine, 

 when saturated wilh muriatic acid gas, was discovered 

 by Mr Kind, apothecary in Entin, while employed in 

 making a medicine called the liquor ar/hritictts Pottii. 

 He put a quantity of oil of turpentine into a Woulfe's 

 bottle, and caused a current of muriatic acid gas, sepa- 

 rated from common salt by sulphuric acid, to pass 

 through it. The salt used was of the same weight with 

 the oil of turpentine. At fir^t the oil became yellow, 

 then brown, and at last became almost solid, from the 

 formation of a great number of crystals in it, which pos- 

 sessed the properties of camphor. 



The proportion of muriatic gas found to answer best, 

 is what can be separated by sulphuric acid and heat from 

 a quantity of common salt equal in weight to the oil of 

 tuiprntine employed. The camphor produced amounts 

 nearly to one-half of the oil of turpentine. 



The camphor thus produced was very white ; it had a 

 peculiar odour, in which that of the oil of turpentine 

 could be distinguished. When washed with water it 

 became beautifully white, and gave no longer signs of 

 containing an acid, but still had the smeil of oil of tur- 

 pentine. Water containing some carbonate of potash de- 

 prived it of part of this odour, b^it not the whole. When 



