stood. This gas issues in considerable quantity from the rocks in the neighbourhood of Brohl near Bonn, and from the small but deep crater-like lake of Laach. It has been computed that 600,000 pounds of this gas are daily evolved from this locality," and there is a vulgar fable that its noxious vapours prove as poisonous to the feathered tribe as those of the far-famed Avernus of Italy. 3 DRYDEN. Probably Alexander's Cave, near Tabriz in Persia, owes its hurtful exhalations to a similar cause. Pliny seems to refer to the Grotto del Cane, when he mentions that above Puteoli, deadly vapours arose from clefts in the ground. 15. There is a valley in Java called the Valley of Death, which doubtless owes its deadly character to the presence of carbonic acid gas in extraordinary abundance, mingled probably with other mephitic vapours. It is thus described by Loudon, who in 1830, made a tour through Java and Madara. Balor, 4th July 1830.-Early this morning we made an excursion to the extraordinary valley, called by the natives Guwo Upas, or Poisoned Valley; it is three miles from Balor, on the road to Djienz. Mr Daendels had ordered a footpath to be made from the main road to the valley. We took with us two dogs and some fowls, to try experiments in 1 Dr Mered. Gairdner-Min. and Therm. Springs, p. 59. 2 Murray's Handb. North. Germ. p. 270. 3 Athen. No. 221. Jan. 21. 1832. Jameson's Edin. New Phil. Jour., vol. xii.; Encyc. Brit. 7th ed. vol. xviii. 183. this poisonous hollow. On ariving at the foot of the mountain we dismounted, and scrambled up the side about a quarter of a mile, holding on by the branches of trees; and we were a good deal fatigued before we got up the path, being very steep and slippery from the fall of rain during the night. When within a few yards of the valley, we experienced a strong nauseous, suffocating smell; but on coming close to its edge, this disagreeable odour left us. We were now all lost in astonishment at the awful scene before us. The valley appeared to be about half a mile in circumference, oval, and the depth from 30 to 35 feet; the bottom quite flat; no vegetation; some very large (in appearance) river-stones; and the whole covered with the skeletons of human beings, tigers, pigs, deer, peacocks, and all sorts of birds. We could not perceive any vapour or any opening in the ground, which last appeared to us to be of a hard sandy substance. It was now proposed by one of the party to enter the valley; but at the spot where we were, this was difficult, at least for me, as one false step would have brought us to eternity, seeing no assistance could be given. We lighted our cigars, and with the assistance of a bamboo we went down within 18 feet of the bottom. Here we did not experience any difficulty in breathing, but an offensive nauseous smell annoyed us. We now fastened a dog to the end of a bamboo 18 feet long, and sent him in; we had our watches in our hands, and in 14 seconds he fell on his back, did not move his limbs or look round, but continued to breathe 18 minutes. We then sent in another, or rather he got loose from the bamboo and walked in to where the other dog was lying. He then stood quite still, and in 10 seconds he fell on his face, and never after wards moved his limbs; he continued to breathe 7 minutes. We now tried a fowl, which died in a minute and a half. We threw in another, which died before touching the ground. During these experiments, we experienced a heavy shower of rain; but we were so interested by the awful sight before us, that we did not care for getting wet. On the opposite side near a large stone, was the skeleton of a human being, who must have perished on his back with the right arm under his head. From being exposed to the weather, the bones were bleached as white as ivory. I was anxious to procure this skeleton, but any attempt to get at it would have been madAfter remaining two hours in this Valley of Death, we returned, but found some difficulty in getting out." ness. 16. Let us suppose with some, that atmospheric air is a chemical compound, an idea argued against by the late Dr Dalton; or grant with that great philosopher that the gases are merely mechanically blended, we cannot too much admire the wisdom of the Creator in adjusting the proportions so exactly for the comfort and preservation of his creatures. We have stated, that 4 vol. of nitrogen and 1 vol. of oxygen form atmospheric air, or to reduce the ratio to the following standard -say, two vol. of nitrogen, and half a vol. of oxygen, compose the air we breathe. Two vol. of nitrogen, and one vol. of oxygen, form the nitrous oxide or laughing-gas of Davy,—a fluid which, when inhaled for a few minutes, intoxicates; but which would be injurious, if not fatal, if breathed for any length of time. Two vol. of nitrogen, and two vol. of oxygen, form the nitric oxide,—a gas which cannot be respired, for, coming in contact with the atmosphere, it is instantly converted into a poisonous acid, the nitrous acid recognised by its ruddy fumes. Two vol. of nitrogen, and three vol. of oxygen, form the hyponitrous acid, which exists only in combination with a base. Two vol. of nitrogen, and four vol. of oxygen, form the nitrous acid already mentioned. Two vol. of nitrogen, and five vol. of oxygen, compose nitric acid or aquafortis, one of the most corrosive and deadly poisons. Thus, of all the combinations of these two gases, atmospheric air is the only one fit for sustaining life! How easily could the destruction of the globe be effected, were the Creator to change the proportions of these fluids! "'Tis sweet to muse upon His skill display'd, Infinite skill in all that He has made !" COWPER,-Retirement. 17. This leads us to refer to a speculation of M. Adolphe Brongniart,' upon the formation of those carboniferous beds which are so widely distributed over our globe, and without which civilization would not have rapidly advanced. To this geologist it has occurred, that, during that era of our earth's history, the atmosphere was much more largely charged with carbonic acid gas than now or previously. During that era, there seems to have been an ascendency in the vegetable over the animal kingdom, for while immense numbers of trees and arborescent ferns and smaller plants existed, scarcely a vestige of land animals is to be found. If we suppose that during that period there was a larger proportion of carbonic acid in the air than now, it would be most favourable to vegetable life, while the excess would be detrimental to that of animal existence. No sooner were those vast coal-fields deposited, than we find a manifestation of animal life, and finally its predominance. We find much luxuriant vegetation in the presence of those waters which are richly charged with carbonic acid gas.2 18. It has been shewn, that the proportions of oxygen and nitrogen in our atmosphere are invariable. Whence the source of the supply of the former gas to compensate its consumption by organic life and combustion? According to Lavoisier and Séguin, an adult man consumes by respiration in 24 hours, 46037 cubic inches, or 32.5 oz. of oxygen. Davy estimates the amount somewhat less, and Menzies slightly greater; but supposing one of these results to be a near approximation to truth, it is evident that the human race alone require for the purposes of life an enormous quantity of this gas, which is separated in the lungs from the other atmospheric ingredients. Boussingault computes the consumption of oxygen by the horse in the same period at 13 lb. 3.5 oz., and by the cow, at 11 lb. 10.75 oz. During expiration nitrogen is thrown off, and the place of the oxygen nearly supplied by carbonic acid 1 Annales des Sciences Naturelles, tom. xv. - 2 Schleiden, Wiegman's Archiv. iii. 1838; Davy,-Consola. in Trav. 3d ed. p. 116. * Ann. de Ch. et de Phys.; Liebig's Organ. Chem. exhaled, together with aqueous vapour.' How, then, are the relative proportions preserved? The expired carbonic acid is absorbed by the vegetable world; its carbon is appropriated as the special food of plants, and by day a larger quantity of oxygen is eliminated than consumed; although during night carbonic acid is given off, it is in a smaller ratio. Here, then, we observe a remarkable reciprocal relation between the vegetable and animal kingdoms. From these facts we are warranted to believe that every tree, plant, and blade of grass contribute their quota to the purification of the atmosphere, and the preservation of the equilibrium of its component parts. But this is not all. Count Rumford long ago discovered that the infusoria evolve oxygen; and recently Liebig and others have drawn attention to the fact. The number of those little creatures far exceeds the power of human ken. Creation teems with their existence, yet all so small that naked vision fails to detect their presence. "Shall little haughty ignorance pronounce His works unwise, of which the smallest part THOMSON, Summer, v. 321. 'See Lavoisier, Séguin, Davy,-Phil. Tr. 1823; Edwards-De l'Infl. des Agens Phys. sur la Vie, Paris, 1824, p. 420 et seq.; Prout, Menzies, Allen, and Pepys,Schweiger's Journ. i. p. 182, and lvii. p. 337; Ph. Tr. 1809; Despretz,-Ann. de Ch. et de Phys. tom. xxvi. p. 337; Dulong,-Schweiger's Jour. xxxviii. p. 505; Andral, Collard de Martigny,-Jour. de Physiol. tom. iv. et x.; Coutanceau,Revision des Doct. Physiologiques; Nisten, Spallanzani, Ellis,-Inq. into changes induced on atmos. air, &c.; Humboldt and Provençal,-Mém. d'Arcueil, tom. ii. ; Bostock,-Physiol. Ch. vii. sec. 3.; Gavarret, Dumas, Valentine, Brunner, Simon, -Anim. Chem. vol. i., &c. 2 Priestley, Davy, Ingenhousz, Woodhouse, Senebier, Saussure, Burnett, Liebig, Daubeny, Boussingault,-Economie Rurale, tom. i. pp. 53-68; Johnston,-Agricult. Chem. &c. |