The quantity of water brought away was too small to examine for the presence of bromine.

This is the last of the thermal waters of Asia Minor which have been examined; there are a few others that may yet reach me, when the composition will be made known as soon as examined.

Cause of the Thermal Waters in Western Asia Minor.

The cause of the abundance of warm springs in this quarter of the globe, in all formations from the alluvial to the oldest rocks, is doubtless owing to the extensive igneous action within no great depth beneath the surface of the country; a fact evinced by the frequency of earthquakes, but more especially by their extent; for they almost invariably extend from one end of it to the other, as well as to the neighboring islands.

Neither time nor change of government has contributed so much to the destruction of the hundreds of magnificent cities. which once covered this country, as the desolating influence of the earthquake, and many are the cities that now exist, which have been prostrated over and over again, and rebuilt, each time in diminished splendor, until at last they are little better than collections of huts when contrasted with their original condition. All the country at the present day seems to be as much subject to them as formerly.

The only part of Western Asia Minor where phenomena are seen strictly analogous to those of active volcanoes, is in the Catacecaumene or burnt district, situated in Lydia, about one hundred miles east of Smyrna. Numbers of volcanic cones exist in the neighborhood of Koola, of many of which the craters are quite distinct, especially the one called Kaplar Alan, which has a perfect crater about half a mile in circumference, and two or three hundred feet deep. The extent of this region is some twenty miles long by eight broad. We have no record of any activity in these volcanoes, and Strabo described them in his day quite as they are now, and the Turks give to Satan the full credit of having created such a black parched-up district. My object at the present time is merely to mention this district, as a full description of it enters into a paper on the earthquakes and volcanoes of Asia Minor, that I propose publishing at some future time; it is brought forward now merely to show what this volcanic centre has to do with the thermal springs just described.

Remarks on the occurrence of Nitrogen in Thermal Waters. -The only substance connected with these waters that I shall allude to, is the nitrogen contained in the gas accompanying many of them, and in some instances constituting almost the entire gaseous product, as in the case of the springs of Yalova. This singular fact attracted my attention several years ago, while

examining into the gaseous products of various springs, and I then ascertained that the gas was found especially with warm springs; the nitrogen, when found accompanied with oxygen, existed in proportions much greater than in the atmosphere, and in numerous instances it was almost pure. The question naturally arises, whence comes this nitrogen? and as we know of no other natural source of nitrogen than the atmosphere, it occurs to the mind that there is a source of the gas in the thermal waters, which, before they pass to the heated substrata, absorb a certain amount of air; the oxygen of the air contained in the water combines with the rocks and minerals, or is taken up by some de-oxydizing agent in the waters, which, as they return to the surface naturally bring the nitrogen of the air freed of all or most of its oxygen.

This explanation, which appears so natural, does not, however, account for the fact, and I have been obliged to abandon it. Did the nitrogen in these waters occur in such small quantities, as we might suppose to have been absorbed by water, the explanation would hold good; but the fact in the case of the springs at Yalova and many other sources, is, that the gas, which is nearly pure, bubbles up in great abundance. Again, if the nitrogen evolved by springs be simply such as the water absorbs before penetrating the surface of the earth, how does it happen that this gas escapes from springs of ordinary temperature? For it is reasonable to suppose that the water having once taken into solution a gas, will not give it out except by heat or the presence of a large amount of saline matter, neither of which occur to explain the evolution of nitrogen gas from certain springs.

Feeling thus satisfied that the nitrogen in the gaseous products of springs is not owing to its absorption from the atmosphere, its origin has been sought for elsewhere, but without success, and I am constrained to believe that nitrogen is one of those elements stored up in the interior of the earth, in more or less abundance, either pure or combined, and frequently finds its way to the surface through those fissures by which mineral waters are conducted. Its more frequent occurrence with thermal waters is doubtless owing to the greater depth from which the latter come.

After all, however, that has been said, we must acknowledge the explanation imperfect, and as only furnishing another evidence of the difficulty of learning anything of the origin or uses of this singular substance, nitrogen in its elementary state. On the Analysis of these waters, particularly with reference to the Silica and Alkalies.

The general method of analysis adopted, differed but little from that usually employed; and the construction of the salts out of the acids and bases has been made entirely from the dictates of my judgment in the matter.

The examination of the silica attracted considerable attention, from the fact that we are in the habit of always estimating it as uncombined silica, even when found in alkaline waters. Although my researches are sufficient to prove to my mind the inaccuracy of this, still I have not thought proper in this paper to deviate from the rule generally adopted, leaving it to more extended research to decide the point.

In the analysis of the waters of Broosa, nearly all of which are alkaline, the following fact has been observed; that on concentrating a considerable quantity of the water to a small bulk, all the carbonate of lime is precipitated and a portion of the silica (whether in combination with lime or not is not yet decided); but a large portion of the same still remains in solution, as well as some lime, although the water is alkaline with an excess of carbonate of soda. The silica is in such quantity that it could remain only in solution in combination with an alkali, in fact there is a silicate of soda and lime present.

The question here arises whether the silica was in a state of combination before the water was concentrated, or is it a result that has taken place during the evaporation; this question can only be decided by more extended investigation.

The observation of the above fact has led me to adopt the following method of estimating the silica in mineral waters. Take a certain quantity of the water, evaporate almost to dryness, add hydrochloric acid, a little more than is required to saturate the carbonates present; continue to evaporate to complete dryness, and then add water acidulated with a little hydrochloric acid, filter and wash the silica that remans on the filter; in this way we are sure to have the silica perfectly free from any silicate.

The method adopted for estimating the alkalies will be mentioned in a few words, as more details of it will be given in a paper devoted especially to that subject, the method has particular reference to the separation of the alkalies from magnesia.

Take the solution filtered from the silica, evaporate to dryness to drive off the excess of acid, add a little water to redissolve, then add pure lime water and filter, when the chlorids of the alkaline metals and calcium with excess of lime will pass through, the magnesia, alumina, oxyd of iron, &c., remaining on the filter. Separate the lime with carbonate of ammonia, or still better with oxalate of ammonia, evaporate to dryness, and heat to drive off the ammoniacal salts, when nothing but the chlorids of alkaline metals will be left which can be separated in the ordi

nary way.

This completes the description of all the thermal waters of Asia Minor which have as yet come under my notice, with the observations that the investigation have given rise to.

ART. XXXIX.-On the Preservation of Animal Substances; by HENRY GOADBY, M.D., F.L.S., formerly Dissector of Minute Anatomy to the Royal College of Surgeons of England.

In the preserving fluids that I use, and which are known by my name, the following ingredients occur, viz.: rock salt, alum, corrosive sublimate, and the white oxyd of arsenic, or arsenious acid.

These materials are never all employed at one time, and they should be used judiciously, to prevent the contingency of destroying, rather than preserving specimens of Natural History.

To this end, I think it desirable to describe the properties of the materials respectively before giving the necessary formulæ for the fluids.

Rock (or bay) salt is very preservative, and will maintain the characteristics of all tissues unimpaired, better than any other agent with which I am acquainted, provided the strength be well regulated; and I make much greater use of the purely sa line, or B fluid, than of any other.

Alum possesses very important conservative properties; it is astringent, coagulates albumen to some extent, rendering transparent tissues opake in proportion to the volume of alum brought in contact with them; but it destroys the carbonate of lime, converting it into the insoluble sulphate. The aluminous, or A, 2, fluid, however, is a very valuable composition; and to it I owe many important preparations, which may be found both in my own possession, and in the Hunterian Museum of the Royal Col lege of Surgeons, of England, and which could never have been made without its assistance.

Alum combines with animal tissues so perfectly, that it cannot be dissolved out of them by long continued maceration in water. Whenever it is considered necessary to use the aluminous fluids either to give form, and support, to an animal, or any part of an animal, or a delicate tissue, by reason of its astringent property, or to render diaphanous animals or tissues opake enough to be visible, the excess of alum should be washed away with water, and the animal or whatever it be, with few exceptions, removed from the aluminous, and preserved permanently in the B fluid. It should be borne constantly in mind that the effect of fresh volumes of the aluminous fluid should be cautiously watched, lest the alum produce mischievous results; but with care, it may even be used to the full extent of its valuable properties on the soft parts of an animal enclosed in a shell of carbonate of lime, or otherwise possessing that earth, for the muscular, nervous, and other soft tissues, will be much sooner affected by the action of the alum than the denser tissues containing earthy matter. It

will hence be seen that the aluminous fluid is not of universal application.

Corrosive sublimate is also astringent, and the coagulator of albumen; the intention of its application is not for the sake of either of these properties, but simply to prevent vegetation growing in the fluids respectively. But inasmuch as albumen takes from corrosive sublimate a portion of its chlorine, and thus converts it into calomel, and as all animal tissues are more or less albuminous, the propriety of using it at all, may well be questioned. In places where the sporules of fungi abound, as in the store-rooms of large museums, not even the presence of corrosive sublimate can prevent them from growing upon the surface of either of my preserving fluids, if they contain animal matter of any kind and are in open vessels, i. e., not hermetically sealed; but, in a long experience of this fact, I am bound to say that, although I have had open jars, dishes, and other vessels containing dissections of animals waiting their turn to be mounted permanently as preparations, in which the surface of the fluid has been covered during the summer months with vegetation of considerable substance, and which has continued to increase, and flourish magnificently for weeks, yet, I have never known it to descend into the fluid, or affect the dissections (provided they were well covered with fluid) in any way. Indeed, either of these fluids will preserve plants, as easily, and certainly, as they preserve animals; and were the fungus to grow into the fluid, it would die, and be preserved. Neither have I at any time, during fourteen years experience of preparations made by the use of my fluids, and contained, and sealed down, in the several forms of vessels and cells, also of my invention, ever found a particle of vegetation. in a single preparation; and during the last six years I have been using the fluids, both for permanent preparations, and stores, without the addition of corrosive sublimate, and always with satisfactory results. I believe, therefore, that the corrosive sublimate may be safely left out, although I shall include it in the recipes of the fluids.

As arsenic acts upon glass and glass vessels, by combining with the lead, and for other reasons, it cannot be employed for preparations that are desired to be permanent. I have made a few such attempts, but they have all ended in failure. Arsenic possesses the power of softening animal tissues to a most remarkable extent, and this property has no limit.

A few years ago I was desired by the examiners in Anatomy, of the University of London, to preserve a body during the summer season for their examinations in the autumn. Desiring to retain the tissues severally in as natural a state as possible, I added arsenic to the B fluid. For some months, nothing could exceed the success of this experiment, and if I had changed the