38 



NATURE 



\Nov. 9, 1 87 1 



complicated processes by whicli the rocky crust of the earth has 

 been .built up, and hy which the present varied contour of the 

 earth's surface has been produced, — to ascertain, in short, from 

 a study of the existing economy of the world, what has been the 

 history of our planet in earlier ages. 



Hitherto, while men had been accustomed to believe that the 

 earth was but some 6,000 years old, they sought in the rocks 

 beneath and around them evidence only of the six days' creation 

 or of the flood of Noah, Each new cosmological system was 

 based upon that belief, and tried in various w.iys to reconcile the 

 Biblical narrative with fanciful interpretations of the facts of 

 Nature. It was reserved for Huttnn to declare, for the first time, 

 that the rocks around us can never reveal to us any trace of tlie 

 beginning of things. He too first clearly and persistently pro- 

 claimed the great fundamental truth of Geology, thnt in seeking 

 to interpret the' past history of the earth as chronicled in the 

 rocks, we must use the present economy of nature as our guide. 

 In our investigauons, ''no powers,' he says, "are to be em- 

 ployed that are not natural to the globe, no action to be admitted 

 of except those of which we know the principle. Nor are we 

 to proceed in feigning causes when those appear insufficient 

 which occur in our experience,"* This was the guiding principle 

 of the Scottish School, and through their influence it has become 

 the guiding principle of modern Gtology, 



There were two direclions in which Hutton laboured, and in 

 each of which he and his followers constantly travelled by the 

 light of the present order of nature — viz., the investigation 

 of (i) changes which have transpired beneith the surface and 

 within the crust ol the earth, and (2) changes which have been 

 effected on the surface itself. 



I. That the interior of the earth was hot, and that it was the 

 seat of powerful forces, by which the solid rocks could be rent 

 open and wide regions of land be convulsed, were familiar facts, 

 attested by every volcano and earthquake. These phenomena 

 had been for the most part regarded as abnormal paits of the 

 system of nature ; by many writers, indeed, as well as by the 

 general mass of mankind, they were looked upon as Divine 

 judgments, specially sent for the punishment and reformation of 

 the human species. To Hutton, pondering over the great 

 organic system of the world, a deeper meaning was necessary. 

 He felt, as Steno and Moro had done, that the earthquake and 

 volcano were but parts of the general mechanism of our planet. 

 But he saw also that they were not the only exhibitions of the 

 potency of subterranean agencies, that in fact they were only 

 partial and perhaps even secondary manifestations of the influ- 

 ence of the great internal heat of the globe, and that the fidl 

 import of that influence could not be understood unless careful 

 study was also given to the structure of the rocky crust of the 

 earth. Accordingly, he set himself for years patiently to gather 

 and meditate over data which would throw light upon that 

 structure and its history. The mountains and glens, river- 

 valleys and sea-coasts of his native country, were diligently tra- 

 versed by him, every journey adding something to his store of 

 materials, and enabling him to arrive continuady at wider views 

 of the general economy of nature. At one time we find him in 

 a Highland glen searching for proofs of a hypothesis which he 

 was convinced must be true, and, at their eventual discoveiy, 

 breaking forth into such gleeful excitement that his attendant 

 gillies concluded he must certainly have hit upon a mine of gold. 

 At another time we read of him boating with his friends 

 Playfair and Hall along the wild cliffs of Berwickshire, again in 

 search of confirmation to his views, and finding, to use the words 

 of Playfair, " palpable evidence of one of the most extraordinary 

 and important facts in the natural history of the earth," 



As a result of his wanderings and leflection, he concluded that 

 the great mass of the rocks which form the visible part of the 

 crust of the earth was formed under the sea, as sand, gravel, and 

 mud are laid there now ; and that these ancient sediments were 

 consolidated by subterranean heat, and, by paroxysms of the 

 same force, were fractured, contorted, and upheaved into dry 

 land. He found that portions of the rock had even been in a 

 fused state ; that granite had erupted through sedimentary rocks ; 

 and that the dark trap-rocks or "whinstones" of Scotland 

 were likewise of igneous origin. 



When the sedimentary rocks were studied in the broad way 

 which was followed by Ilutton and his associates, many pruufs 

 appeared of ancient convulsions and re-formations of the earth's 

 surface. It was found that among the hills the strata were often 

 on end, while on the plains they were gently inclined ; and the 



" Hutton's "Theory of the Earth," I, p, 160; it p. 549. 



inference was deduced by Hutton that the former series must 

 have been broken up by subterranean commotions before the 

 accumulation of the latter, which was derived from its debris. 

 He conjectured that the later rocks would be found actually 

 resting upon the edges of the older. His search for, and dis- 

 covery of, this relation at the Siccar Point, on the Berwickshire 

 coast, are well described by his biographer Playfair, who accom- 

 panied him, and who, dwelling on the impression which the 

 scene had left upon him, adds : " The mind seemed to grow 

 giddy by looking so far into the abyss of time ; and while 

 we listened with earnestness and admiration to the philosopher 

 who was now unfolding to us the order and series of these 

 wonderful events, we became sensible how much farther reason 

 may sometimes go thnn imagination can venture to follow." Sir 

 James Hall afterwards, by a series of characteristically inaenious 

 experiments, showed how the rocks of that coast-line may have 

 been contorted by movements in the crust of the earth under 

 great superincumbent pressure. 



Hutt<m was the first to establish the former molten condition 

 of granite, and of many o:her crystalline rocks. He maintained 

 that the combined influence of subterranean heat and pressure 

 upon sedimentary rocks could consolidate and mineralise them, 

 anfl even convert them into crystalline masses. He was thusth^ 

 founder of the modern doctrine's of metamorphism regarding the 

 gradual transformation of marine sediments into the gnarled and 

 rugged gneiss and schist of which mountains are built up. Let 

 me quote the eulogium passed upon this part of his work in an 

 cs*ay by M, Daubree, which eleven years ago was crowned with 

 a prize by the Academy of Sciences at Paris : — " By an idea 

 entirely new, the illustrious Scottish philosopher showed the 

 successive co-operation of water and the internal heat of the 

 globe in the formation of the same rocks. It is the mark of 

 genius to unite in one common origin phenomena very different 

 in their nature," '■ Hutton explains the history of the globe with 

 as much simplicity as grandeur. Like most men of genius, 

 indeed, who have opened up new paths, he exaggerated the 

 extent to which his conceptions could be applied. But it is 

 impossible not to view with admiration the profound penetration 

 and the strictness of induction of so clear-sighted a man, at a 

 time when exact observations had been so few, he being tlie first 

 to recognise the simultaneous effect of water and heat in the for- 

 mation of rocks, in imagining a system which embraces the whole 

 physical system of the globe. He estalilished principles which, 

 in so far as they are fundamental, are now universally admitted." 

 {To be continued) 



SCIENTIFIC SERIALS 

 Aiiimleii dcr Chemie und Pharmacie, clix,, for July, opens 

 with a concluding communication "On the constitution of the 

 twice substituted benzenes," by E, Ador and V, Meyer. The 

 authors converted sulphanilic acid into bromobenzine-sulphonic 

 acid, and fused the potassium salt of this acid with potassic hy- 

 drate. The dihydroxylbenzine produced was found to be resorcin ; 

 Meyer and others have proved that resorcin belongs to the 1 : 4 

 series, and therefore sulphanilic acid must also be regarded as 

 containing the SO^H and NH, in the places i and 4 respectively. 

 Sulphanilic acid treated with nitrous acid yields a diazo-derivative 

 C^HjN.SOj, this on boiling wiih water is converted into phenol- 

 sulphonic acid, which was found to be identical with Kekule's 

 paraphenolsulphonic acid. At the end of the communication, a 

 valuable table of the twice substituted benzines, showing the place 

 of attachment of the second substituted group is given ; it however 

 differs in some respects from the arrangement of other chemists. 

 Ernst and Zvvenger have prepared ethyl and amyl gallates by 

 passing hydrochloric acid through a boiling solution o' gallic acid 

 in the anhydrous alcohols ; at present they have not succeeded in 

 preparing the methyl gallate, — A very exhaustive paper follows 

 "On some substances crystallised from microcosmic salt and 

 from borax," by A. Knop, in which the crystallisation of phos- 

 phostannic, phosphozirconic, and phosphoniobic acids from 

 microcosmic salt, and of stannic acid, zirconic acid, noria, and 

 niobic acid from borax are thoroughly discussed, — Lichen and 

 Rossi have prepared "normal valeric acid" by the action of 

 boiling alcoholic potash on butyl cyanide, ihey find that the 

 valeric acid thus obtained does not agree in properiies with either 

 of the acids already known. They have also prepared normal 

 amylic alcohol from the above acid, by heating the calcic valerate 

 with calcic formiate, the valeric aldehyde being converted into 

 amylic alcohol by the action of sodium amalgam. The alcohol 



