1855.] 



PREPARATION OF ALUMINIUM. 



361 



of the proof that the crystalizatioa of New Eagland took place after 

 the coal age. Fossils in Maine and Vermont add to the evidence. 

 The quiet required over the continent, for the regular succession and 

 undisturbed condition of the rocks of the Silurian, Devonian and Car- 

 boniferous formations, shows that in neither of those ages could such 

 vast results of metaniorphic action and upheaval have taken place. 



The length of time occupied by this revolution is beyond all esti- 

 mate. Every vestige of the ancient Carboniferous life of the conti- 

 nent disappeared before it. In Europe a Permian period passed with 

 its varied life ; yet America, if we may trust negative evidence, still 

 remained desolate. The Triassic period next had it3 profusion of liv- 

 ing beings in Europe, and over 2,000 feet of rocks. America, through 

 all, or till its later portions, -was still a blank , nor till near the be- 

 ginning of the Jurassic period do we find any traces of new life, or 

 even of another rock above the Carboniferous. 



What better evidence could we have than the history of the oscilla- 

 tions of the surface, from the earliest Silurian to the close of the Car- 

 boniferous age, and the final cresting of the series in this Appalachian 

 revolution, that the great features of the continent had been marked 

 out from the earliest time? Even in the Azoic, the same north-cast 

 and south-west trend may be observed in Northern New York and be- 

 yond Lake Superioi-, showing that although the course of the great 

 Azoic lands was partly east and west, the same system of dynamics 

 was then to some extent apparent, or at least in development. 



The first event in the records after the Appalachian revolution is 

 the gathering up of the sands and fragments of the crystalizcd rocks 

 and schists along the Atlantic border into beds — not over the whole 

 surface, but in certain valleys which lie parallel with the Appalachian 

 chain, and which are evidently a result of the foldings of that revolu- 

 tion. The beds are the red sandstone and shales which stretch on for 

 1-0 miles in the Connecticut Valley; and similar strata occur in 

 South-eastern New York, in New Jersey, Virginia and North Carolina. 

 These long valleys .are believed to have been estuaries or river courses. 

 The period of these deposits is regarded as the earlier Jurassic by 

 Prof. Wm. PI. Rogers. Dr. Hitchcock supposes that a portion of the 

 preceding or Triassic period may be represented. Many of the Layers 

 show by their shrink-cracks, ripple marks and foot prints, as others 

 have observed, that they were formed in shallow waters, or existed 

 as an exposed mud flat. But they accumulated till they were 

 over a thousand feet thick in Virginia, and in New England two or 

 three thousand, according to the lowest estimate. Hence the land 

 must have been sinking to a depth equal to this thickness, as the 

 accumulations went on, since the layers were formed successively at 

 or near the surface. 



Is it not plain, then, that the oscillations, so active in the Appala- 

 chian revolution, and actually constituting it, had not altogether ceased 

 their movements, although the times were so quiet that numerous 

 birds and reptiles were tenants of the Connecticut region ? Is it not 

 clear that these old valleys, occurring at intervals from Nova Scotia 

 to South Carolina, originally made by foldings of the earth's crust, 

 were still sinking? 



And did not the tension below of the bending rocks finally cause 

 ruptures? Even so. And the molten rock of the earth's interior 

 which then escaped through the crystaline rocks beneath and the over- 

 lying sandstone, constitutes the trap mountains, ridges and dykes, 

 thickly studding the Connecticut Valley, standing in palisades along 

 the Hudson, and diversifying the features of New Jersey and parts of 

 Virginia and North Carolina. The trap is a singularly constant at- 

 tendant on the sandstone, and everywhere bears evi<lenco of having 

 been thrown out soon after the deposition of the sandstone, or in con- 

 nection with the formation of its later beds. Even the small sand- 

 stone region at Southbury, Ct., has its trap. Like the .-Yppalachian 

 revolution this epoch had its greatest disturbances at the North. 



Thus ended in fire and violence, and probably in submergence be- 

 neath the sea, the quiet of the Connecticut Valley, where lived, as wo 

 now believe, the first birds of creation — kinds that were nameless until 

 some countless ages afterward. Prof. Hitchcock tracked them out, 

 found evidence that they were no unworthy representatives of the 

 feathered tribe, and gave them and their reptile associates befitting 

 appellations. 



Such vast regions of eruptions could not have been without effu- 

 sions of hot water and steam and copious hot springs. .\nd may not 

 those heated waters and vapors, rising up through the crystaline rocks 

 below, have brought up the copper ores that arc now distributed in 

 some places through the sandstone ? The same cause, too, may have 

 given the prevalent red color to the rock, and produced changes in 

 the adjoining granite. 

 3 



After the era of these rocks, there is no other American record 

 during the European Jurassic period. 



In the next, or Cretaceous period, the seas once more abound in 

 Animal life. The position of the Cretaceous beds around the Atlantic 

 border show that the continent then stood above the sea very much as 

 now, except at a lower level. The Mississippi Valley, which from the 

 Silurian had generally been the region of deeper waters, was even in 

 Cretaceous times occupied to a considerable extent by the sea — the 

 Mexican Gulf then reaching far north, even far up the Missouri, and 

 covering also a considerable part of Texas. 



An age later, the Cretaceous species had disappeared, and the 

 Mammalian Age (or the Tertiary, its first period,) begins, with a. 

 whollj' new Fauna, excepting, according to Prof. Tuomey, some half 

 a dozen species, about which, however, there is much doubt. The 

 continent was now more elevated than in the preceding age, and the 

 salt waters of the Mexican Gulf were consequently withdrawn from 

 the region of Iowa and Wisconsin, so as not to reach beyond the 

 limits of Tennessee. 



Two or three times in the course of the Tertiary period, the life of 

 the seas was exterminated, so that the fossils of the later Tertiary are 

 not identical with any in the earliest beds, excluding some fish re- 

 mains — species not confined to the coast waters. The crust of the 

 earth was still oscillating; for the close of the first Tertiary epoch 

 was a time of subsidence; but the oscillation or change of level was 

 slight, and by the end .of the Tertiary, the Continent on the east stood 

 within a few feet of its present elevation, while the Gulf of Mexico 

 was reduced nearly to its present limits. 

 [To be continued.'^ 



Preparation of Aliuufuinm* 



The following are two methods given by M. St. Claire Deville for 

 obtaining Aluminium: — 



1. SoDiD.M Process. — Introduce into a glass tube of about an inch 

 in diameter from 200 to 300 grammes of chloride of aluminium, closing 

 the ends with a plug of asbestos ; then conduct hydrogen gas, dry, and 

 perfectly free from atmospheric air, into the tube, and heat the 

 chloride of aluminium in this current of gas by means of charcoal. 

 This will h.ave the etfect of driving off' the hydrochloric acid, chloride of 

 silicium, and chloride of sulphur, with which it is always impregnated. 

 Capsules of as large size as possible, containing each some grammes 

 of sodium, previously crushed between two sheets of dry filter paper 

 .are then introduced into the glass tube. The tube "being full of 

 hydrogen, the sodium is melted ; and the chloride of aluminium on 

 being heated, will be distilled and decomposed with incandescence 

 which may be easily moderated. The operation will be complete when 

 all the sodium has disappeared, and the chloride of sodium formed, 

 has absorbed a sufficient quantity of chloride of aluminium to saturate 

 it. The aluminium will now exist in the state of a double chloride of 

 aluminium and sodium, which is a very fusible and volatile compound, 

 the capsules are next to be removed from the glass tube, and placed in 

 a large porcelain tube, furnished with a pipe leading to a receiver. 

 Through this porcelain tube, while heated to a lively red heat a 

 current of hydrogen, dry and free from air, is caused topass ; and the 

 chloride of aluminium and sodium will be thereby distilled without 

 decomposition, and collect in the receiver. .Vfter the operation, nil 

 the aluminium will be found collected in the capsules in the form of 

 large globules; these are washed in water, which will carry off a little 

 of the salt produced by re-action, and also some brown silicium. In 

 order to form a single mass of all these globule.", after being clean.sed 

 and dried, they are introduced into a capsule of porcelain, into which 

 is put, as a flux, a small quantity of the product of the preceding 

 operation — i. e., of the double chloride of aluminium and sodium. On 

 heating the capsule in a mutlle to the temperature of about the molting 

 point of silver, all the globules will be seen to unite in a brilliant ma.s9 

 which is allowed to cool, and then washed. The melted metal must bo 

 kept in a closed porcelain crucible until the vapours of the chloride of 

 aluminium and soilium with which the metal is impregnated have 

 entirely disappeared. The metallic ma'^s will then be found surrounded 

 by a light pellicle of alumina arising from the partial decomposition of 

 the flux. 



2. rnorr.ss dv mk.\ns of Galv.vnism.— This process is carried on 

 by means of the double chloride of aluminium and sodium. For this 

 purpose the aluminium bath is prepareil by taking two parts by 

 weight of chloride of aluminium, and adding thereto one part of dry 



