1853] 



EXTRACTS FROM EXHIBITION LECTURES. 



169 



ammonia and the tar were partially condensed in tubes kept cool, 

 the sulphuretted hydrogen and cai'bonic acid were removed by 

 lime, and the ammonia by washing the gas with water. This 

 last operation was the least ett'ecti\e, and new substitutes had to 

 be de\ised, one of which I may mention ; superphosphate of 

 lime, consisting of bones dissolved in sulphuric acid, only required 

 ammonia to make it a powerful and excellent manure ; trays of 

 this superphospbate were therefore placed in a chamber through 

 wliich the gas passed, and thus the ammonia was removed, 

 while the phos]3hate became enriched. A new method is now 

 extensii'ely employed, and shows the tendency to simplification 

 resulting from discovery. By this method almost all the condi- 

 tions of purification are satisfied by one process ; the gas, after 

 cooling, is at once taken into a chamber containing carbonate of 

 lime and sulphate of iron ; these, reacting upon each other, 

 produce oxide of iron and sulphate of lime. The gas, streaming 

 through this mixture, gi\-es up its sulphuretted hydrogen to the 

 oxide of iron, while the carbonate of ammonia, decomposing the 

 lime salt, forms sulphate of ammonia and carbonate of lime, the 

 lime thus being reconverted to its original state ; the gas before 

 before being piissed into this mixture is occasionally led through 

 chloride of calcium in order to aid the removal of the ammonia- 

 cal salt. When the mixture has done its work it is exposed to 

 air, and the sulphide of iron absorbing oxygen is conveited into 

 a basic sulphate of iron ; hence the mixture is similar in its 

 purifying character, except that it contains sulphate of ammonia, 

 which may be washed out and preser\-ed, while the retidue is 

 employed over and over again. By this elgant process the noxi- 

 ous sulphur compounds are utilized in the tabrication of sulphate 

 of ammonia, and the mixture seems never weary of peiforming 

 its duty ; hence not only is the purification perfoi'med at one 

 process, but the noxious ingredients are converted into compounds 

 of much value. The waste and badly-smelling products of gas- 

 making appeared almost too bad and foetid for utilization, and 

 yet eveiy one of them, Chemistry, in its thriftiness, has made 

 almost indispensible to human progress ; the badly-smelling tar 

 yields benzole, an ethereal body of great solvent powers, well 

 adapted for preparing varnishes, used largely for making oil of 

 bitter almonds, of value for removing gi-ease-spots, and for 

 cleansing soiled white kid gloves. The same tar gives naphtha, 

 so important as a solvent of Indian rubber and gutta percha; 

 similar tar, when made from wood, yields creosote, a powerful 

 preservative of animal matter, and much employed as a medici- 

 nal agent. Coal-tar furnishes the chief ingredient of printer's 

 ink, in the foi-m of lamp-black ; it substitutes asphalte for pave- 

 ments ; it forms a charcoal when mixed with red-hot clay, that 

 acts as a powerful disinfectant. When the tar is mixed with the 

 coal-dust, formerly wasted in mining operations, it forms by 

 pressure an excellent and compact artificial fuel ; the water con- 

 densed with the tar, contains much ammonia, readily convertible 

 into sulphate of ammonia, a salt now recognised as being of great 

 importance to agriculture, and employed in many of the arts. 

 Cyanides are also present among the products of distillation, and 

 these arc readily oon-serted into the beautiful colour known as 

 Prussian blue. The naphthaline, an ememy to the gas-manu- 

 faeter by choking the pipes, may be made into a beautiful red 

 colouring matter, closely resembling that from madder. This, 

 by its transformation, promises an impoi-tant, hitherto not yet 

 realised useful product. Coal, when distilled at a lower temper- 

 ature than that required to form gas, produces an oil containing 

 paraffin, lai-gely used as an antifrictional oil for light machinery. 



In the isolated cases of manufactures, adduced .is types of the 

 importance of chemical appliances to industry, I have referred to 

 general subjects rather than to individual objects in the Exhibi- 

 tion ; because these Lectures ought, in obedience to the desire of 

 their Royal suggester, to be indications of consequences rather 

 than, references to .special excellencies. The illustrations have been 



restricted to Chemistry, not that I unduly exalt its importance, 

 but that we are wisely instructed to confine our attention to the 

 branch of knowledge most familiar to us. All these instances, 

 however, are real consequential supports of a text which has 

 already been discussed in its general bearings in another Lecture.* 

 The text was this, — that the progress of absti-act science is of ex- 

 treme importance to a nation depending upon its manufactures. 

 It is only the oveiflowings of Science, ai'ising from the veiy ful- 

 ness of its measuie, that benefit industry. When water falls fiora 

 a higher to a lower point, it, to a certain extent, increases the velo- 

 city of the rotiition of the earth, and the sum of the increments of 

 the velocity of all falling wateis would soon be sensible, were it 

 not that the sun, lapping them up, restores them to their sources, 

 and by removing them farther from the centre, compensates for 

 the increased velocity given in one locality ; while at the same 

 time they fertilize the lands on which they fall. So is it with 

 Science and Industry. The overflowings of abstract Science give 

 their first impulse to the country producing them ; but the Sun 

 of knowledge soon raises and distributes them to all lands, which 

 receive benefit in just so far as the ground is prepared for their 

 fertilizing influence. The discoverer of absti'act laws, however 

 apparently remote from practice, is the real benefactor to his 

 kind ; in reality, far more so than he who applies them dii'ectly 

 to industr}'. Yet in our Mammon-worahip we adore the golden 

 calf, and do not see its real creator. It is abstract and not prac- 

 tical Science that is the life and soul of Industry; practical ap- 

 pliances are the organs through which the God-born truths pass 

 for the sustenance of its general fiame. The cultivators of abstract 

 Science, the searchei-s after truth, for eternal truth's own sake, are 

 — to borrow a simile. I believe of Canning — the horses of the 

 chariot of industry ; those who usefully apply the truths are the 

 harness by which the motion is communicated to the chariot. But 

 is the chariot drawn by the horses or the harness ? Truth to say, 

 in this country of ours, and mark you well, in no other country 

 in Europe, — we honour the hai-ness, but neglect the horses. It is 

 the harness that is gilt; the hard-working horees too often receive 

 but meagre fare. Now, in all this, I tell you a living truth ; one 

 far more connected with the actual material progress of our nation 

 than you may be aware of. The ]Hiblishecl opinions of Babbage 

 and Herechel, men who have a right to ])ronounce judgment on 

 this subject, assui-e us that England is lapidly declining in Science. 

 It is most important that we should ascertain the real cause of 

 this decline. The cause would appear to be, that we chiefly 

 honour those who are useful in our time and generation ; that our 

 eyes are too eagerly bent upon the golden prize, for which we are 

 all running ; and that we can only aftbrd to throw a kind of 

 theoretical squint of recognition on those men, who ai'e looking 

 for sublime truths, cai'eless as to whether they will have any 

 immediate eftect on industrial jirogress. And yet it is these very 

 men that give strength to the sinews of a future genei-ation, 

 enabling it to keep its place in the industrial sti'uggle of nations. 

 Do not misunderstand me. Science never looks so beautiful as 

 when she aids man to increase his resources and comforts ; but 

 the dove would not liave brought the olive-branch to the aik of 

 man's hopes unless she had been able to take a higher and a longer 

 flight than that embraced in the tree whence she came. 



It is no new truth that both absti-act Science and Art should 

 have a position intimately allied with, but still thorouglily inde- 

 pendent of. Industry. I read mythology wrongly, unless this is 

 strongly shadowed out in the history of the gods. Vulcan, the 

 god of Industr)", wooed Minerva with a passionate love, but the 

 chaste goddess never mari-ied. keeping always independent, 

 although no celestial ever showered so many benefits on the 

 peaceful arts. Aitistic beauty, in the person of Venus, was really 



* " Ou the National Importance of Studying Abstract Science ■n itli a 

 view to the Healthy Progress of Tndvistry." By Lyon Playfair, 

 C.B.F.R.S.— H. M. StatioDery Office. 



