Our attention was next directed to the various modes of analyzing atmospheric air, and discovering the proportions of its component parts, and the lecturer very familiarly explained the different instruments called Eudiometers, employed by Priestley, Gay, Lussac, Davy, Schell, Hope, Volta, and Ure, all of which, when carefully experimented with, agree in exhibiting the same proportions between the oxygen and nitrogen gas, of a given proportion of atmospheric air, at all times and in all situations.

We are however still ignorant of the way in which these gases of the atmosphere exist together. We can only conceive, that they are either mechanically mixed, or chemically combined. Each of these modes have been proposed by eminent individuals, and supported by ingenious arguments in proof. Berthollet and Dr. Murray argue for the chemical union; but our townsman, Dr. Dalton, has given an explanation in favour of the mechanical doctrine, highly characteristic of his profound acuteness of reasoning. Dr. Dalton supposes that the particles of any gas are highly repulsive of themselves, and hence why a portion would fill a space in proportion to the pressure, but that the particles of two different gases do not repel each other. It follows from this supposition, that one gas acts as a vacuum with respect to another: that is, a gas will rise in the interstices between particles of another kind, without any repulsive hinderance, and therefore, a heavy gas springs up by its own elasticity, through the

substance of a lighter gas, whilst the lighter gas forces through the interstices of that at first placed beneath it.

An experiment in proof of this was exhibited. A small glass vessel filled with oxygen, was connected by a long tube with another phial containing nitrogen, the contents being as four to one. The arrangement was made an hour or two before the lecture commenced, and on the contents being tested, it was found that the heavier gas had ascended, and the lighter descended, so that the gases were completely mingled, and each phial contained atmospheric air; thus conclusively establishing the theory of Dr. Dalton, which unlike chemical theory, is applicable to every possible case, and likewise accounts for the equable diffusion of vapour through gases, and through each other.

This tendency to be diffused, varies with the density according to the experiments of Mr. Graham, of Glasgow; which fact might also have been inferred from the facility of evaporation in a rarified atmosphere. This extraordinary subject is still under investigation, but the explanation manifestly depends rather on the mechanical constitution of gases, than on any chemical principle.

So far as we have reported this interesting lecture, atmospheric air has been considered as consisting of two gases, oxygen and nitrogen, but, as the lecturer stated, there is another gas called carbonic acid, or fixed air, according to the old nomenclature, always found in it, though some understand pure air to consist

of only the two elements, oxygen and nitrogen; viewing carbonic acid gas as an extraneous mixture, resulting from combustion, respiration, &c. Carbonic acid gas is detected by exposing to the atmosphere substances which readily attract and combine with it at natural temperatures. It forms not only a constituent part of the atmosphere, near the surface of the earth, but at the greatest heights, which the daring and industry of man have been able to penetrate. Saussure found it at the summit of Mount Blanc, the highest point of the European continent, a point covered with eternal snow, and not exposed to the influence of vegetables or animals. Although it is difficult to determine the exact amount of this gas in the air, it is very easy to demonstrate its existence. Lime-water rapidly attracts it; so does a solution of pure alkali. Sometimes this gas is freely formed by the decomposition going on in dark, damp cellars, vaults, old walls, and other places which we may incautiously venture to enter: being heavier than common air, it does not so easily pass away; and, as it is destructive to life, it is important, in these cases, that it should be absorbed. Its presence may be easily discovered by a lighted candle; if carried into carbonic acid gas, its flame is immediately extinguished. The lime-stone rock is nothing but lime and carbonic acid, and mortar is supposed to set or harden in our walls by its lime again uniting with a portion of carbonic acid from the atmosphere.

Hydrogen gas is said to have been found in air,

R

situated near the crater of volcanoes; and it is very possible that it may exist always in a very small portion in the atmosphere; but this cannot be ascertained, till some method of detecting the presence of hydrogen, combined with a great proportion of the air, be discovered.

A substance, possessing the singular property of inflaming spontaneously, when it comes into contact with atmospheric air, frequently rises from church-yards and marshes, supplied by the decomposition of phosphoric and vegetable matters. Chemists call this phosphuretted hydrogen, but it is better known by the names of Jack o'lantern, Will o' wisp, ignis fatuus, and wandering fire.

The lecture was concluded by an interesting account of those singular substances occasionally falling from the atmosphere, termed meteoric stones, and by a brief summary of the leading facts developed in the preceding observations, from which it appears that pure air consists of four proportions, by measure, of nitrogen, and one of oxygen gas, with a small portion of carbonic acid gas; and the infinite variety of substances which mingle with the lower atmosphere are adventitious, and rise but little above the source which furnishes them. And we may therefore consider, that the important share which this great aereal ocean takes in the operations of nature, is the effect of the mere mechanical mixture of two elementary gases. As we proceed with this instructive subject, we cannot fail to be

struck with admiring wonder, in viewing the simple means by which the Creator produces the beautiful harmony, and extensive usefulness, of this interesting portion of his works.

Manchester Times, 1833.

ON THE LANGUAGE OF THE ENGLISH BIBLE.

It is a striking beauty in our English Bible, that, though the language is always elegant and nervous, and for the most part very harmonious, the words are all plain and common, no affectation of learned terms, or of words of Greek or Latin etymology. I have sometimes amused myself with the simplicity and harmony of particular passages. Nothing can be more melodious than the following, which yet seems to be the effect of accident rather than of art:-"Man that is born of a woman is of few days, and full of trouble. He cometh up (or forth) as a flower, and is cut down ; he fleeth also as a shadow, and continueth not." Virgil himself would not versify the following passage, for fear of hurting its harmony; and yet every word is common, and there is not the least appearance of art in the composition. "My beloved spake and said unto me, Rise up my love, my fair one, and come away. For, lo! the winter is past, the rain is over and gone. The flowers appear on the earth, the time of the singing of birds is come; and the voice of the turtle is heard in our land. The fig-tree putteth forth her green figs, and the vines with the tender grape give a goodly smell. Arise my love, my fair one, and come away."