From Chambers' Journal. OZONE. RECENTLY, the singular gas termed ozone has attracted a large amount of attention from chemists and meteorologists. The vague ideas which were formed as to its nature when as yet it had been but newly discovered, have given place gradually to more definite views; and though we cannot be said to have thoroughly mastered all the difficulties which the strange element presents, yet we know already much that is interesting and instructive. Let us briefly consider the history of ozone. mediately in the office that a servant is summoned to such-and-such a room on suchand-such a floor. In the bath-room there are two brass pipes, from which the water flows. One pipe furnishes hot water, the other cold, the quantity of which may be regulated at pleasure. In all these arrangements, all establishments are fitted up alike. 14th. Fine. Settled the dates for our journey to Holland and other countries. The Secretary of State, Ka (the Earl of Clarendon), invited me to an interview with him in the afternoon, when, in addition to other conversation, he stated that the Queen had spoken approvingly of me, and also that, being aware I was about to visit other coun- Nine years after Priestley had discovered tries, he had been good enough to send oxygen, Van Marum, the electrician, nocommunications notifying the fact, in order ticed that when electric sparks are taken that wherever I went I might find hospitable entertainers. This is kindness and attention for which one should certainly feel grateful. Went next to the Earl of T.'s, where a large party of distinguished guests were invited, and where the lady of the house treated me with the utmost hospitality. After a time we repaired to the garden, and looked on while the lady visitors played at ball (croquet), during which time music was discoursed by a band. The assemblage of elegant toilettes was truly a sight to behold! 20th. Rain. The Duke of P. invited us to a public assembly to witness a ball. The number of guests of both sexes was considerable (lit. exceeded several tens). All the officials present wore their court uniforms, the same as at the palace entertainment. It was 2 A.M. when I got back to the hotel. The majority of the guests, it was stated, were Scottish, and of the ladies two or three in every ten had white hair, though their faces were youthful and blooming. In answer to my inquiries I was told that the hair was artificially whitened. One not conversant with the fact might almost have taken youthful matrons for grandmothers! 22nd. Mr. B. of the Crystal Palace invited us to see the fountains. The landscape scenery and grottoes which they went through with us were very pretty sights. Returned home after a dinner in the evening. It was close upon midnight when we got back. On this day we saw a native of the province of Hu-peh, not more than three feet high, and also a man from Ngan-hevei, eight or nine feet in height - both remarkable specimens of humanity. A foreigner has brought them for a tour in this country. 23rd. Fine. At 9 A.M. embarked on board a steamer and left port for Holland. through that gas, a peculiar odour is evolved. Most people know this odour, since it is always to be recognized in the neighbourhood of an electrical machine in action. In reality, it indicates the presence of ozone in the air. But for more than half a century after Van Marum had noticed it, it was supposed to be the smell of electricity." In 1840, Schönbein began to inquire into the cause of this peculiar odour. He presently found that it is due to some change in the oxygen; and that it can be produced in many ways. Of these, the simplest, and, in some respects, the most interesting, is the following: "Take sticks of common phosphorus, scrape them until they have a metallic lustre, place them in this condition under a large bell-jar and half-cover them with water. The air in the bell-jar is soon charged with ozone, and a large room can readily be supplied with ozonized air by this process." Schönbein set himself to inquire into the properties of this new gas, and very interesting results rewarded his researches. It became quite clear, to begin with, that whatever ozone may be, its properties are perfectly distinct from those of oxygen. Its power of oxidizing or rusting metals, for example, is much greater than that which oxygen possesses. Many metals which oxygen will not oxidize at all, even when they are at a high temperature, submit at once to the influence of ozone. But the power of ozone on other substances than metals is equally remarkable. Dr. Richardson states that, when air is so ozonized as to be only respirable for a short time, its destructive power is such that gutta-percha and india-rubber tubings are destroyed by merely conveying it. The bleaching and disinfecting powers of ozone are very striking. Schönbein was at first led to associate them with the qualities the combination of two special forms of of chlorine gas; but he soon found that they are perfectly distinct. It had not yet been shewn whether ozone was a simple or a compound gas. If simple, of course it could be but another form of oxygen. At first, however, the chances seemed against this view; and there were not wanting skilful chemists who asserted that ozone was a compound of the oxygen of the air with the hydrogen which forms an element of the aqueous vapour nearly always present in the atmosphere. It was important to set this question at rest. This was accomplished by the labours of De la Rive and Marignac, who proved that ozone is simply another form of oxygen. Here we touch on a difficult branch of modern chemical research. The chemical elements being recognized as the simplest forms of matter, it might be supposed that each element would be unchangeable in its nature. That a compound should admit of change, is of course a thing to be expected. If we decompose water, for instance, into its component elements, oxygen and hydrogen, we may look on these gases as exhibiting water to us in another form. And a hundred instances of the sort might be adduced, in which, either by separating the elements of a compound, or by rearranging them, we obtain new forms of matter without any real change of substance. But with an element, the case, one would suppose, should be different. However, the physicist must take facts as he finds them; and amongst the most thoroughly recognized chemical facts we have this one, that elementary substances may assume different forms. Chemists call the phenomenon allotropy. A well-known instance of allotropy is seen in red phosphorus. Phosphorus is one of the chemical elements; and, as every one knows, the form in which it is usually obtained is that of a soft, yellow semi-transparent solid, somewhat resembling bees'-wax in consistence, poisonous, and readily taking fire. Red phosphorus is the same element, yet differs wholly in its properties. It is a powder, it does not readily take fire, and it is not poisonous. Ozone, then, is another form of oxygen. It is the only instance yet discovered of gaseous allotropy. oxygen the positive and the negative; or, as he called them, ozone and antozone. He shewed that, in certain conditions of the air, the atmospheric oxygen exhibits qualities which are the direct reverse of those which ozone exhibits, and are distinct from those of ordinary oxygen. In oxygen thus negatived, or antozonised, animals cannot live any more than they can in nitrogen. The products of decomposition are not only not destroyed as by ozone, but seem subject to preservative influences, and speedily become singularly offensive; dead animal matter rapidly putrefies, and wounds shew a tendency to mortification. But the theory of positive and negative forms of oxygen, though still held by a few physicists, has gradually given way before the advance of new and sounder modes of inquiry. It has been proved, in the first place, that ozone is denser than ordinary oxygen. The production of ozone is always followed by a contraction of the gas's volume, the contraction being greater or less according to the amount of oxygen which has been ozonized. Regularly as the observers - Messrs Andrews and Taitconverted a definite proportion of oxygen into ozone, the corresponding contraction followed, and as regularly was the original volume of the gas restored when, by the action of heat, the ozone was reconverted into oxygen. And now a very singular experiment was made by the observers, with results which proved utterly perplexing to them. Mercury has the power of absorbing ozone; and the experimenters thought that if, after producing a definite contraction by the formation of ozone, they could absorb the ozone by means of mercury, the quantity of oxygen which remained would serve to shew them how much ozone had been formed, and thence, of course, they could determine the density of ozone. Suppose, for instance, that we have one hundred cubic inches of oxygen, and that by any process we reduce it to a combination of oxygen and ozone occupying ninetyfive cubic inches. Now, if the mercury absorbed the ozone, and we found, say, that there only remained eighty-five cubie inches of oxygen, we could reason in this way: - Ten cubic inches were occupied by And now we have to deal with the diffi- the ozone before the mercury absorbed it; cult and still-vexed questions of the way in but these correspond to fifteen cubic inches which the change from oxygen is brought of oxygen: hence, ozone must be denser than about, and the actual distinction between oxygen in the proportion of fifteen to ten, the two forms of the same gas. Schönbein or three to two. And whatever result holds that common oxygen is produced by might have followed, a real absorption of the ozone by the mercury would have as satisfactorily solved the problem. But the result actually obtained did not admit of interpretation in this way. The apparent absorption of the ozone by the mercury, that is, the disappearance of the ozone from the mixture, was accompanied by no diminution of volume at all. In other words, returning to our illustrative case, after the absorption of the ozone from the ninety-five cubic inches occupied by the mixture, there still remained ninety-five cubic inches of oxygen; so that it seemed as though 0 cubic inches of ozone corresponded in weight to five cubic inches of oxygen. This solution, of course, could not be admitted, since it made the density of ozone infinite. The explanation of this perplexing experiment is full of interest and instruction. We follow the account recently given by Mr. C. W. Heaton (Professor of Chemistry at Charing Cross Hospital) in the pages of a scientific contemporary, slightly modifying it, however, so that it may better suit our columns. cubic inches of oxygen gave up their atoms, each atom combining with one of the remaining oxygen doublets, so as to form a set of ozone triplets. Clearly, then, fifteen cubic inches of oxygen were transformed into ozone. They now occupied but ten cubic inches; so that the mixture, or ozonized oxygen, contained eighty five cubic inches of oxygen and ten of ozone. When the mercury was introduced, it simply transformed all the ozone triplets into oxygen doublets, by taking away the odd atom from each. It thus left ten cubic inches of oxywhich, with the remaining eighty-five, constituted the ninety-five cubic inches observed to remain after the supposed absorption of the ozone. It follows, of course, that ozone is half as heavy again as oxygen. "this But, as Mr. Heaton remarked, beautiful hypothesis, although accounting perfectly for all known facts, was yet but a probability. One link was lacking in the chain of evidence, and that link M. Soret has supplied by a happily devised experiment." ~ Although mercury and most substances are only capable of converting ozone into oxygen, oil of turpentine has the power of absorbing ozone in its entirety. Thus, when the experiment was repeated, with oil of turpentine in the place of the mercury, the ozone was absorbed, and the remaining oxygen, instead of occupying ninety-five inches, occupied but eighty-five. After this, no doubt could remain that Dr. Odling's ingeniously conceived hypothesis was the correct explanation of Messrs. Andrews and Tait's experiment. Modern chemists adopt, as a convenient mode of representing the phenomena which gases exhibit, the theory that every gas, whether elementary or compound, consists of minute molecules. They suppose that these molecules are of equal size, and are separated by equal intervals so long as the gas remains unchanged in heat and density. The view serves to account for the features of resemblance presented by all gases. The features in which gases vary are accounted for by the theory that the molecules are differently constituted. The molecules are We recognize, then, in ozone a sort of supposed to be clusters of atoms, and the concentrated oxygen, with this peculiar qualities of a gas are assumed to depend on property, that it possesses an extraordinary the nature and arrangement of these ulti-readiness to part with its characteristic third mate atoms. The molecules of some elements atom, and so disappear as ozone, two-thirds consist but of a single atom; the molecules of its weight remaining as oxygen. of others are formed by pairs of atoms; those of others by triplets; and so on. Again, the molecules of compound gases consist of combinations of different kinds of atoms. It is to this peculiarity that ozone owes the properties which render it so important to our welfare. We are indeed, as yet, in no position to theorize respecting this element, our knowledge of its very existence being so recent, and our information respecting its presence in our atmosphere being of still more recent acquisition. Now, Dr. Odling, to whom we owe the solution of the perplexing problem described above, thus interpreted the observed phenomena. A molecule of oxygen contains two atoms, one of ozone contains three, and Indeed, it is well remarked by Mr. Heathe oxydizing power of ozone depends on the ton, that we had, until quite lately, no reaease with which it parts with its third atom son for confidently adopting Schönbein's of oxygen. Thus, in the experiment which view that ozone exists in our atmosphere. perplexed Messrs. Andrews and Tait, the The test-papers which Schönbein made use mercury only seemed to absorb the ozone; of turned blue under the influence of ozone, in reality it converted the ozone into oxy-it is true, but they were similarly influenced gen by removing its third atom. And now by other elements which are known to exist we see how to interpret such a result as we in our atmosphere, and even the sun's rays considered in our illustrative case. Five turned them blue. However, Dr. Andrews has shown how the character of the air pro- | formed into oxygen. It parts with its third ducing the change can be further tested, so atom as in the mercury experiment, and thus as to render it certain that ozone only has loses its distinctive peculiarity. Thus we been at work. If air which colours the test- might be led to anticipate the results which papers can be found to lose the property come next to be considered. after being heated, the change can only be due to ozone, because nitrous and nitric acid (which have the power of colouring the test-papers) would not be removed by the heat, whereas ozone is changed by heat into Oxygen. Once we are certain that ozone exists in the air, we must recognize the fact, that its presence cannot fail to have an important bearing on our health and comfort; for ozone is an exceedingly active agent, and cannot exist anywhere without setting busily to its own proper work. What that work is, and whether it is beneficial or deleterious to ourselves, remains to be considered. In the first place, ozone has immense power as a disinfectant. It decomposes the products emanating from putrefying matter more effectually than any other known element. Perhaps the most striking proof ever given of its qualities in this respect is that afforded by an experiment conducted by Dr. Richardson a few years ago. 66 He placed a pint of blood taken from an ox in a large wide-mouthed bottle. The blood had then coagulated, and it was left exposed to the air until it had become entirely redissolved by the effects of decomposition. At the end of a year the blood was put in a stoppered bottle, and set aside .for seven years. "The bottle was then taken from its hiding-place," says Dr. Richardson, and an ounce of the blood was withdrawn. The fluid was so offensive as to produce nausea when the gases evolved from it were inhaled. It was subjected by Dr. Wood and myself to a current of ozone. For a few minutes the odour of ozone was destroyed by the odour of the gases from the blood; gradually the offensive smell passed away; then the fluid mass became quite sweet, and at last a faint odour of ozone was detected, whereupon the current was stopped. The blood was thus entirely deodorized; but another and most singular phenomenon was observed. The dead blood coagulated as the products of decomposition were removed, and this so perfectly, that from the new clot that was formed serum exuded. Before the experiment commenced, I had predicted on theoretical grounds that secondary coagulation would follow on purification; and this experiment, as well as several others afterwards performed, verified the truth of the prediction." It will of course be understood that ozone in thus acting as a disinfectant is trans Oxone has certain work to do, and in doing that work is transmuted into oxygen. It follows, then, that where there has been much work for ozone to do, there we shall find little ozone left in the air. Hence, in open spaces where there is little decomposing matter, we should expect to find more ozone than in towns or cities. This accords with what is actually observed. And not only is it found that country air contains more ozone than town air, but it is found that air which has come from the sea bas more ozone than even the country air, while air in the crowded parts of large cities has no ozone at all, nor has the air of inhabited rooms. So far as we have gone, we might be disposed to speak unhesitatingly in favour of the effects produced by ozone. We see it purifying the air which would otherwise be loaded by the products of decomposing matter, we find it present in the sea-air and the country air, which we know to be so bracing and health-restoring after a long residence in town, and we find it absent just in those places which we look upon as the most unhealthy. Again, we find further evidence of the good effects of ozone in the fact, that cholera and other epidemics never make their dreaded appearance in the land when the air is well supplied with ozone- or in what the the meteorologists call the ozone-periods." And though we cannot yet explain the circumstance quite satisfactorily, we yet seem justified in ascribing to the purifying and disinfecting qualities of ozone our freedom at those times from epidemics to which cleanliness and good sanitary regulations are notedly inimical. But there is a reverse side to the picture. And as we described an experiment illustrating the disinfecting qualities of ozone before describing the good effects of the element, we shall describe an experiment illustrating certain less pleasing qualities of ozone before discussing the deleterious influences which it seems capable of exerting. Dr. Richardson found that when the air of a room was so loaded with ozone as to be only respirable with difficulty, animals placed in the room were affected in a very singular manner. "In the first place," he says, "all the symptoms of nasal catarrh and of irritation of the mucous membranes of the nose, the mouth, and the throat were rapidly induced. Then followed free se cretion of saliva and profuse action of the | ods, though characterized by the absence of skin-perspiration. The breathing was certain diseases, bring with them their own greatly quickened, and the action of the forms of disease. Apoplexy, epilepsy, and heart increased in proportion." When the other similar diseases seem peculiarly assoanimals were suffered to remain yet longer ciated with the ozone-periods, insomuch within the room, congestion of the lungs that eighty per cent. of the deaths occurring followed, and the disease called by physi- from them take place on days when ozone cians "congestive bronchitis was set up. is present in the air in larger quantities than A very singular circumstance was noticed usual. Catarrh, influenza, and affections also as to the effects of ozone on the differ- of the bronchial tubes, also affect the ozoneent orders of animals. The above-men- periods. tioned effects, and others which accompa- We see, then, that we have yet much to nied them, the description of which would learn respecting ozone before we can probe out of place in these pages, were devel-nounce definitely whether it is more to be oped more freely in carnivorous than in her- welcomed or dreaded. We must wait unbivorous animals. Rats, for example, were til the researches which are in progress have much more easily influenced by ozone than been carried out to their conclusion, and rabbits were. perhaps even further modes of inquiry will have to be pursued before we can form a definite opinion. The results of Dr. Richardson's experiments prepare us to hear that ozone-peri Beyond the low black line Of trees the dawn peeps red; A fresh and glistening dew, And tremble through and through. And lane and alley and street A human shape comes, dark. While over the dew-drench'd green, She is nameless, she is dull, The lark sings sad and low: Never a soul is clean. The city is dark; the wrong is deep; Who is he, the stooping one, He has weigh'd the winds and floods; He is crafty, and can prove God is Brahma, Christ, nor Jove; The lark cries, "Praise to Nature's plan! Till the beast flowers up in man; |