I8J7.J 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



185 



> ears' hard working of the apparatus, it is found that each cask (including 

 hulls, puncheons, and liie Urger description of casks), exceeds little 

 beyond 2^d., or one-fuurtii what it costs by Ihe present system. 



Wood seasoned by tliis process is particularly applicable to floor boards, 

 and house tiitiocs generally, for cabinet work, n)usical instruments, car- 

 riage building, &c., as shown by the annexed table : — 



Comparative Strength of Various kinds of Wood in a " Seasoned" and 

 " Unseasoned" state. 



Mames of Wood 

 4 bearing 1 inch 

 square. 



Fir seasoned.. 



do 



do 



Fir not seasd. . 



do. . . . 



do.... 



Elm seasoned 



do 



do 



Elm not seasd, 



do 



do 



Ash seasoned 



do 



do 



Ash not seasd 



do 



do 



Beech seasond. 



do.... 



do.... 

 Beech not seas. 



do.... 



do.... 



Oak seasoned . 



do 



do 



Oak not seasd. 



do 



do 



Weight. 



M6 

 1-17 

 119 

 118 

 1 15 

 105 



1-33 



1-3 



1-4 



115 



1-21 



1-36 



1-56 

 1-51 

 1-16 

 1-41 

 1-38 

 1-34 



1-85 



1-76 



1-81 



1-73 



1-8 



1-78 



1-68 

 1 88 

 1-45 

 1-84 

 1-89 

 1-85 



Weight 



after 

 Hot Air. 



1-09 

 108 

 1-1 



1-21 

 1-18 

 1 27 



1-44 

 1-38 

 1-33 



1-71 



1-G2 

 163 



1-73 

 1-77 

 1-36 



I Deflec- 

 molBturel tion in 

 removed iitclies & 



I tenths 



•07 

 ■09 

 ■09 



•12 

 ■12 

 •13 



•12 

 •13 

 •13 



•14 

 •14 



•18 



•15 

 •11 



■09 



3-5 

 33 

 40 

 3-6 

 3-8 

 40 



3-5 



5^ 



4-3 



6-5 



5-7 



6 1 



4- 



68 



61 



8^ 



85 



8^ 



5-5 



6- 

 5- 



6-2 

 6-9 

 (>■ 



Break- 

 ing 



Weight 

 in lbs. 



201 

 190 

 214 

 190 

 190 

 176 



120 

 106 

 128 

 106 

 99 

 110 



234 

 252 



218 

 176 

 162 

 1G9 



257 

 279 

 280 

 176 

 180 

 148 



299 

 270 



218 

 227 

 232 



8-8 or nearly 9 

 [per cent. added to 

 [strength of Fir by 



seasonins. 



~] 12-3 per cent. 

 I added to strength 

 ' of EIni by sea- 

 soning. 



44-7 per cent. 

 I added to strength 

 I of Ash by sea- 

 soning. 



61-9 per cent, 

 added to strength 

 of Beech by sea- 

 soning. 



T 261 per cent, 

 'added to strength 

 [of Oak by season- 



AGK OF VOLCANOES. 



At the Royal Institution, April 30, W . R. Hamilton, Esq., in the chair, 

 a paper was read " On the A^^e of the VoUanoes of Auvergne as determined 

 by the Remains nf successive Groups of Lund Quadrupeds." By C. Lyell, 

 Esq. 



The region of extinct volcanoes of Auvergne derives its peculiar interest 

 from the circumstance of its never having been submerged beneath the sea 

 during a period in which its geological and geographical structure, and Ihe 

 animals and plants by which it iias been inhabited, have undergone a great 

 succession of changes. In the rest of Europe generally the volcanic rocks 

 have either been origiu.illy of submarine origin, or the surface since they 

 were produced has sufl'ered so much denudalion by the action of the waves 

 of the ocean as to make it impossible for us to ascerlain the form and man- 

 ner in which the eruptions took place, or the relative position which the 

 igneous formations helil at tirst to the hills, plains, and valleys then exist- 

 ing. After describing the s.-veral classes of rocks iu Auvrrgne — the granite, 

 Ihe eocene freshwater, and the older and modern volcanic, each depicted 

 by different colours in an extensive landscape enlarged from a view of the 

 valley of C'hambon (Huy de Dome) by Mr. P. Scrope.— Mr. Lyell said he 

 should dwell chiefly on the antiquity to be ascribed to Ihe Puy de Tar- 

 taret, a type of one of the most modern cones of eruption in Central France. 

 The comparatively recent origin of Ihis conical hill of scoriae, with its crater 

 at the summit, is proved by its standing at the botlotn of a deep valley e.ic- 

 cavated through the alternating beds of putnice, trachyte, and basalt, be- 

 longing to the more ancient volcano of Mont Dor, and partly through the 

 subjacent and fundainenlal granite. It is farther coulirmed by Ihe course 

 of a powerful current of lava ; which, proceeding from the base of the cone, 

 flows thirteen miles down the channel of the River Couze, stopping at the 

 town of Nechers, near Issoire. The lava occupies the ancient river-bed, 

 ani is observed to contract in its dimensions iu the narrow gorges, where 

 it also gains in height, like the water of a river flowing through the arch of 

 a bridge; and to expand agaia where the valley op-us, where it spreads 



into a broad sheet having a level surface. It also flows up the channels of 

 ributary streams till it attains a level corresponding with the top of Ihe 

 lava at the point of junction of the tributary with the main valley. But 

 although these appearances prove that the lava has flowed as it would now 

 do If It were remelted and made again to descend the same channel, it 

 nevertheless bears in some part of its course the marks of considerable 



Before considering these, Mr. Lyell entered into a short digression to re- 

 fute the doctrine of li.e medieval origin of the volcanoes near Clermont, 

 advanced by a writer,,, the Quarterly R^iew for October 1844 (p. 295) 

 where ,t is pretended that .Sidonius Apollinaris, Bishop of Clermont, who 

 flourished at the close of tl,e hllh century, has borne explicit testimony to 



the volcanic eruption, the crumbling of the cones, and the heaping up of 

 the showers of ashes and scoria cast forth am.dst the fires." The passages 

 relied on occur in a letter from Sidonius to his contemporary, Mamertus, 

 Bishop of \,enne,,„ Uauphiny, written when Auvergne was threatened 

 wiih a fresh irruption of the Goths; to avert which danger the Bishop 

 proposes to adopt certain forms of prayer (rogations or litanies), which 

 Maniertus had already introduced on the occasion of some " prodigies" 

 wh.ch had happened in Dauphiny sixteen years before. In alludii.g to 

 Ihese phenomena, hidonius says ihaf the walls of the city of Vienue were 

 shaken by frequent earthquakes, many fires broke out, and mounds of 

 ashes were heaped up over the fallen copings of the walls." •' Nam modo 

 scena; moenium publicorum crebns terra; molibus conculiebantur, nunc 

 ignes sajpe flammati caducas culminum cristas, superjecto favillarum monte 

 lumuiabant • Lieer also took refuge in the forum, and the people fled ; 

 all but the Bishop, « ho had a riglit to reckon on divine protection, because, 

 as h,don,us remiu.ls h,m, on a former occasion, the flames at his approach 

 had miraculously receded out of reverence to his holy person. At the 

 time of the earthquake he (Mamertus) had told his people that their re- 

 pentant tears would extinguish the fires sooner than rivers of water, and 

 the steadfastness of their faith would cause the ,ocking of the ground to 

 cease. Sidonius finishes with asking the Bishop of Vienne to send hiiu 

 sonie relics to make all secure. The style of Ihe whole epistle is so faulty, 

 ambitious, and poetical, as to make it difficult lo know the exact value of 

 tlie expressions, and dangerous to found upon them any philosophical 

 argument about natural events. There is not a word about Auvergne, but 

 simply an allusion to the shocks which appear lo have thrown down build- 

 ings and caused (as usual in such cases where roofs fall in) great confla- 

 grations and heaps of cinders. The terror of the wild animals when the 

 earth rocks, and their sensitiveness lo Ihe slightest movements, are well 

 known. Altbongh Ihe epistle proves Sidonius to have had a fair share of 

 the credulity of his age, both in respect to miracles wrought in favour of a 

 contemporary saint and Ihe efficacy of relics, it would be unfair to charge 

 him with a belief in Ihe occurrence of a volcanic eruption at or near the 

 site of Ihe city of Vienne, which the invesligalion of the ablest government 

 survejors, to whom the construction of a geological map of France has been 

 intrusted, has entirely di.-proved. There are, in fact, no monuments of 

 volcanoes, ancient or modern, iu Dauphiny ; and if there had been they 

 would not throw light on the date of eruptions in Auvergne. 



But to return lo ihe lava-stream of the Puy de Tartaret before alluded 

 to— what geological antiquity can we assign to it.' In one of the gorges 

 the enliie mass of solid basalt has been swepl away by the torrent, so that 

 the former continuity of the stony current is interrupted for several hundred 

 yards, at a point about midway between its efflux from the cone and its 

 termination. This implies a long period of excavation. In another place, 

 about one mile and a half from St. Nectaire, an old Roman bridge, still 

 passable, having two arches, each fourteen feet wide, spans a deep ravine, 

 cut by the Couze through the middle of the lava, which is here of columnar 

 structure. The bridge is supposed by French architects and antiquaries 

 to be of the date of about the filth century; yet the springing of the arches 

 prov. s thai when it was erected the ravine was of the same width as now. 

 Nevertheless, while signs of denudation such as these attest the vast 

 amount of removal of hard rock since Ihe lava flowed and was consolidated, 

 the contemporary cone of loose, incoherent scoriie has stood in its exposed 

 position at ihe very bottom o( a valley, entire and uninjured, the rain-water 

 being instantly absorbed by the porous mass; and no rill being allowed to 

 collect on Its flanks. It is clear that if any flood of water had passed over 

 Auvergne, if any inundation had raised Ihe Lake of Chambon thirty or 

 forty feet, it must have carried away the perishable cone. The lake alluded 

 to owes its origin lo the damming up of the Couie by the volcano and by 

 landslips which accompanied the eruption. 



But the most conclusive evidence, according lo Mr. Lyell, of Ihe remote- 

 ness of the period at which the cone and lava of Tartaret originated has 

 yet to be set forth, and has only been distinctly brought to light since he 

 revisited Nechers in 1843, when the Abb^ Croizel pointed out to him a 

 locality near the lower extremity of the great current, where fossil bones 

 of extinct animals had been discovered iu a meadow, between the base of 

 the lava and the chaunel of the Couze, now ten feet lower in level than the 

 lava. In company with Mr. Bravard, Mr. Lyell explored the spot; and 

 they convinced Ihemsehes that the bone-deposit passed under Ihe lava, 

 which here forms a mass thirty feet thick. Subsequent investigations not 

 only contiriu this view, but have enabled Mr. Bravard lo oblaiu from be- 

 neath the stony current a cousiderable uuu,ber of additional osseous re- 

 mains, referable to the genera Equus, Sus, Taraudus, Cervus, Cauis, 

 Felis, Martes, Putorius, Sorex, Talpa, Arvicola, Spermophilus, Lagomys, 

 Lepus, and accordiug to Mr. Waterhouse, Cncetus or hamster, aud others, 



