28o 



NATURE 



[July 20, 1893 



process was etnployed, but the double advantage was soon seen 

 of avoiding the nuisance of polluting the streams into which 

 the waste liquors were allowed to flow, and of regaining a 

 quantity of soda at a small cost. With the general adoption of 

 esparto as a material a radical change in the manufacture of 

 paper was effected, and the difficulties in which the industry had 

 been placed by reckles-i commercial legislation with regard to 

 foreign rags in a great degree removed. 



" What has taken place in the manufacture of paper has been 

 paralleled in numerous other departments of commercial enter- 

 prise, and not the least in those connected with the manufacture 

 of chemical products themselves, in many, if not indeed in 

 most of which a complete revolution has been effected within 

 the last fifty years, or even less. It would be a hopeless task to 

 try to indicate the whole of the advances in chemical knowledge 

 that have been made within that period, and yet I am tempted 

 to give some few reminiscences of the condition of the science as 

 exhibited in Brande's Elimenis of Chemistry, published in 

 May, 1841, exactly twelve months after my first introduction to 

 business, when compared with our knowledge at the present 

 day. 



" Chemistry at that time was by no means in its infancy. Its 

 foundations had been securely laid not only on the Continent, 

 but in this country, and the names of Priestley, Cavendish, 

 Scheele, Lavoisier, Davy, Wollaston, and other English inves- 

 tigators were already household words. There were, in 1841, 

 twelve simple -non-metallic substances known, from oxygen to 

 boron, including selenium, and forty-three metals from potas- 

 sium to silicium, including lantanum and thorinum. For all 

 fifty-five, symbols had been arranged, but these were in many 

 respects different from those which are now in universal use. 

 C, for instance, stood for chlorine and not for carbon, while B 

 symbolised bromine and not boron. Potassium was designated 

 by Po and not by K, and sodium by So and not by Na, while 

 uranium was known as Urnm and not as U. 



" The atomic weights of the various substances had been 

 approximately determined, though modern investigations have 

 in some instances materially changed their ratio. Though hydro- 

 gen has retained its place as the unit, oxygen is no longer 

 represented by S, but by 1 5 '96, or even less. Sulphur that was 

 then 16 is now 31 '98. Selenium, instead of 40, has now 78 

 assigned to it ; while the number for tellurium has been in- 

 creased fourfold from 32 to 128, .and phosphorus has gone up 

 from 16 to 30'96. Whether all our present figures will stand 

 the test of time remains to be seen, and indeed recent researches 

 have shown cause to doubt the accuracy of some of the figures 

 that I have quoted. For myself, as a somewhat profane out- 

 sider, I must confess that it would be a source of satisfaction if 

 future investigations should show that the figures now having 

 three or four places of decimals attached to them might more 

 properly be converted into integers, and oxygen came out boldly 

 as 16, and sulphur as 32. This is, however, a digression. 



"Turning to the simple substances and metals of which, as 

 already stated, 12 and 43 respectively were known in 1841, we 

 find them now slightly increased. Of non-metals we reckon 

 15, and of metals 48. Some metals, like columbium and 

 glucinum, have dropped out of our list, the latter having now 

 become beryllium, while others, likeciesium, didymium, erbium 

 and rubidium, have come in. 



"On the whole, the changes and advances in inorganic 

 chemistry have not been extreme. It is in organic chemistry 

 that what cannot be regarded as anything short of a revolution 

 has taken place. It is not a matter on which I can dilate, but 

 as indicative of what has been going on I may mention that 

 while three volumes have sufficed to Roscoe and Scholemmer 

 for inorganic chemistry, no less than six have already appeared 

 in continuation treating of organic chemistry, and more are to 

 follow ; so that the proportions have been reversed which pre- 

 vailed in the days of Brande, who devoted 367 pages only to 

 organic chemistry, and 1042 to introductory matter and 

 inorganic chemistry. 



"But whatever may have been the advances in chemistry within 

 the last fifty years, whether as a pure or an applied science, the 

 extension of its boundaries towards physics in the one direction, 

 and biological studies in the other, is at least as remarkable. 

 While the study of spectrum analysis has rendered most 

 valuable assistance in the chemistry of the constituent substances 

 with which we are familiar upon earth, it has enabled the 

 astronomer to carry his speculations not only to the constitution 

 of the sun and stars, but to that of nebulae, comets and meteors, 



NO. 1238, VOL. 48] 



and in the hands of Mr. Norman Lockyer and Mr. Huggins 

 may yet lead us to travel with some degree of confidence in 

 paths hitherto untrodden. In the domain of electricity it is 

 hard to say whether that science does not owe nearly as much 

 to chemistry as chemistry does to it. In the practical application 

 of electricity to lighting purposes, chemistry has still to be called 

 on to produce some improved form of secondary battery, and 

 some portable form of primary battery which shall prove of 

 ready application by our miners. It is needless to recall how 

 much our underground workers are indebted to chemistry for 

 their comparative immunity from danger from fire-damp, a 

 danger which the efforts now being made by chemists will, I 

 hope, still further diminish. Electricity has also placed at the 

 command of chemists greater intensity of heat than can be 

 derived from ordinary sources. 



■"The study of heat, irrespective of electricity, has largely re- 

 acted on chemistry, and while the Bessemer process has entirely 

 revolutionised the manufacture of steel, and almost annihilated 

 the distinction in value between that and other forms of iron, 

 the Siemens and other furnaces have led to unprecedented 

 economies in the expenditure of fuel, and at the same time have 

 facilitated the application of heat in various chemical processes. 

 In the other direction — the absence of heat — Prof. Dewar has, 

 during the present year, made most important advances. 

 Although air had previously been liquefied, he has now been 

 able, by means of intense cold alone, to reduce atmospheric air 

 to the liquid condition. His further results, by a combination 

 of enormous pressure and extreme cold, are well known, and 

 now that oxygen and nitrogen have yielded themselves to the 

 advances of science and have been obtained in quantities in a 

 liquid state, it is hard to say that hydrogen is destined always 

 to remain intractable. What may be the ultimate result of the 

 investigations that can now be carried on at temperatures 

 ranging from 100° to 200° centigrade below the freezing point 

 of water, it is impossible to foresee. From researches already 

 made in this country and in France, it would appear that most 

 substances under extreme cold are, so to speak, dead, and that 

 their ordinary affinities are in abeyance. Possibly what may 

 be termed ' glacial chemistry ' may eventually enlarge our 

 views as to the various properties of matter. 



"As to the advances in our knowledge of the chemistry of light, 

 the present condition of photography may testify. When \ire 

 can take the image of a bullet flying at the rate of 3,000 feet 

 per second, with its accompanying cone of compressed ai - ; 

 when we can produce photographs which are practically perma- 

 nent, and when we call in the action of light to engrave oar 

 steel or copper plates, and to produce efficient substitutes fjr 

 woodtuts, we seem to be getting near the limits of the practical 

 application of photography. And yet many of us may remember 

 the days when the daguerrotype was regarded — and justly so 

 — with wonder ; and I can myself call to mind a still earlier 

 form of photography, by which natural leaves were reproduced 

 on paper sensitised with a salt of silver, of which I saw speci- 

 mens in an exhibition at Dresden so long ago as the year 1S39. 



"In the introduction of artificial light much also has becji 

 done. It is true that Pall Mall was experimentally lighted by 

 gas in 1807, but it was not until 1842 that gas found its way 

 into Grosvenor-square and some.other aristocratic quarters of the 

 metropolis. Since that time immense strides have been made 

 in the process of gas manufacture, while, in consequence of 

 the waste products arising in the process having now found 

 commercial uses, great reductions have been made in its cost. 

 At the present time gas has to compete with electricity as an 

 illuminant, while, in many cases, it has been superseded by 

 mineral oils, which are now so abundant and cheap, and of 

 which in this Society the flashing point may be said to be almost 

 a burning question. If, however, gas is losing ground as an 

 illuminant, it seems to be gaining it as a source of power, and 

 there are prospects of a considerable increase in the use for this 

 purpose of hydrogen and its compounds, containing far less 

 carbon than ordinary coal-gas. 



" In metallurgy also, in addition to the improvements in the 

 manufacture of steel already mentioned, many noteworthy 

 discoveries have been made. One of the most important of 

 these is perhaps that of the production of aluminium on a 

 cheap scale and in quantities suflicient for various applications 

 to ordinary use. It seems somewhat remarkable that the pro- 

 gress in the use of a metal at once so light and so strong is not 

 more rapid. 



" The applications of some of the more modern alloys, such as. 



