The following simple equation, therefore, explains the reaction which has taken place : Action of Sulphuric Anhydride on Phosphorous Chloride. The ease with which the foregoing reaction had taken place led me to try the action of the anhydride on a compound which, possessing latent affinities and a predisposition to combine with oxygen, it was to be expected would cause the separation of the "extraradical" oxygen atom, as I term the atom which is signalized by its great mobility. The compound chosen was phosphorous chloride. On adding this to the anhydride, which must be in a flask surrounded by ice, a violent reaction takes place, attended by a copious evolution of sulphurous anhydride. No further action is observable after equal equivalents have been employed; and on distilling the resulting liquid and fractioning two or three times, two products are obtained, the one boiling from 110° to 114°, which, from all its properties, is undoubtedly phosphoric oxychloride. The reaction has therefore partly taken place as was expected, and according to the equation PC1, + SO, = POCI, + SO,. The second product, which is obtained in varying quantity, according as more or less anhydride is employed, the more being formed, the greater the proportion of the latter *, boils at the first distillation between 120° and 170°, and cannot be obtained of constant B.P., even by repeated rectification, by each of which it only suffers further decomposition, a thick varnishlike residue remaining every time. This product contains phosphorus, chlorine, and sulphur. H. Rose, who also studied this reaction, though without observing the formation either of phosphoric oxychloride or of sulphurous anhydride, which latter he only remarked was given off on subsequent distillation, also describes this second product; he ascribes to it, however, an exceedingly complicated formula. It is very possible that a further substitution of chlorine by oxygen has taken place, as explained by the equation POCI,+2SO, = PO CI+S,O,CL; and this compound can be viewed as metaphosphoric chloride, which it is to be expected would be of a very unstable nature. The above product is then, on this supposition, a mixture of two chlorides, to decide which it will be first necessary to institute experiments with pure phosphoric oxy * It is probable that only phosphoric oxychloride would be formed were the experiment reversed, and the anhydride allowed to act on an excess of the phosphorous chloride. and sulphochlorides; it may then be possible to separate the products of the reaction by means of distillation under reduced pressure. The formation of phosphoric oxychloride in this reaction can be considered as the result of the simple addition of oxygen to phosphorous chloride, the triatomic phosphorus becoming pentatomic*. On the Properties and several Reactions of Pyrosulphuric Chloride. Pyrosulphuric chloride was first obtained by H. Rose by the action of sulphuric anhydride on chloride of sulphur S,CI,, and later on by simple distillation of chloride of sulphur saturated with chlorine with Nordhausen sulphuric acid. Rosenstiehl prepared it by heating sodic chloride with sulphuric anhydride, 3SO, +2NaCl == SO,Cl,+Na,SO. According to him, acetylic chloride is formed by heating it with sodic acetate, and chlorochromic acid by its action on potassic chromate, sodic and potassic pyrosulphates being formed at the same time, as he proved by analysis, K,CrO + S,O,CI, = On passing its vapour through a tube heated to dull redness, I have found the following decomposition to take place :-During the whole operation chlorine and sulphurous anhydride escaped, and in the receiver, which was kept cold by ice, sulphuric anhydride and a liquid layer were condensed. The latter yielded on distillation two products, the one boiling below 100° and the other consisting of the pyrosulphuric chloride which had escaped decomposition. The first portion was found to be sulphuric anhydride contaminated with traces of pyrosulphuric chloride; for on passing a stream of dry carbonic anhydride through it the whole solidified. The decomposition is therefore expressed by the equation The result of a vapour-density determination, according to Dumas's method, also speaks for the above decomposition. The following are the observations recorded: mm. Weight of globe+dry air at 14°-7 and 758-9.... Residual air which gave a specific gravity=5.06. 11 50.513 .... The calculated number for S,O,Cl, 2 vol. is 14.89; a splitting up into SO,+SO,CI, being admitted, it is 7-44; and if the decomposition go further, * Experiments were also made to oxidize carbonic oxide; but the anhydride was found to be without action on it up to a temperature of 200°. I have no doubt, nowever, that the employment of a somewhat higher temperature will effect the combination. and SO,, SO,, and Cl, are the final products obtained on heating, 4·96 is the theoretical number. The experimental number, however, lies between the two latter, and it is therefore to be supposed that already, at a temperature of 200°, the dissociation was almost complete. I intend making a series of determinations at varying temperatures and pressures, especially as H. Rose and Rosenstiehl have obtained numbers very different from mine; the former gives 8.96 as the mean of 5 concordant experiments all made at about 200°, and the latter 7.52, the temperature at which the determination was made not being given in this case. The action of phosphoric chloride on the chloride is somewhat remarkable. On bringing the two together a violent action takes place, and sulphurous anhydride and chlorine escape; after adding slightly more than 1 equivalent of the chloride and 1 equivalent phosphoric chloride, and warming a short time, the latter had entirely disappeared. On distilling but little passed over below 130°, the greatest portion between 130° and 140°, and from 140° to 150° about one-third of the whole. Under all circumstances the formation of phosphoric oxychloride was to be expected, and it was therefore remarkable that so little had distilled over within the limits of its boiling-point. The analysis of the three fractions, however, has shown that they are all mixtures of POCI, and S,O,Cl, in varying proportions. From fraction 1 (130°),— 1655 grm. gave '409 grm. AgCI ⚫4027 grm. gave 1395 grm. BaSO =61.1 Cl. = 4.75 S. 165 grm. gave '0777 grm. Mg,P10,=13·15 P. 2 The amount of phosphorus shown by analysis corresponds to 65-1 POCI; but the amount of chlorine remaining after deduction of that required by the phosphorus and the sulphur are not in the proportion required either by sulphuric chloride or by pyrosulphuric chloride: it is therefore probable that a mixture of both is present. The second fraction still contained 20.8 POCI. 12.5 POCI,. Sulphuric chloride, which it at first seemed probable would be the sole product beside phosphoric oxychloride, has, if at all, only been formed in very small quantity, it seems. As to the constitution of the body S,O,Cl, all seems to speak for its being the chloride of pyrosulphuric acid (so-called Nordhausen), to which it bears the same relation as sulphuric chloride to sulphuric acid,— SO,HO (SO,CI SO, {HO, SO, { CI3 {SO,HO' (SOCI The old view of considering Nordhausen sulphuric acid as merely a solution of sulphuric anhydride in ordinary sulphuric acid has now probably but few partisans among chemists, it being looked upon as a true chemical compound, although of a very unstable nature, for the reason that on one side definite (sodic and potassic) salts of it are known, and on the other it presents analogies with certain chromium and phosphorus compounds, in which groups we are acquainted with the following series: PO(HO), SO,HO (SO,Cl (Cro,HO (CrO,HO (CrO,Cl The peculiar crystalline compound which plays an important part in the sulphuric-acid manufacture is also very possibly a derivative of pyrosul SO,NO* phuric acid, thus:-O SO,NO, ; and I hope to be able to prove this by the action of sulphuric anhydride on CH(NO), or C (NO,).• IV. "On some of the more important Physiological Changes induced in the Human Economy by change of Climate, as from Temperate to Tropical, and the reverse." By ALEXANDER RATTRAY, M.D. (Edinb.), Surgeon R.N., H.M.S. 'Bristol.' Communicated by GEORGE BUSK, F.R.S. Received May 3, 1870. Besides its obvious bearing on the long-vexed and still unsettled question of the unity of the human species, and on the closely related one of acclimatization, the present inquiry is of great medical importance. Tropical pathology, whether of native or foreign races, cannot be fairly studied until we thoroughly know its physiology; nor can we recognize and properly estimate disturbed action of organs till we understand their healthy functions. Otherwise natural phenomena may be mistaken for symptoms of sickness. Many so-called tropical diseases are merely exaggerations of the ordinary effects of climate, physiological merged into pathological phenomena; a knowledge of the one is the first step to an accurate acquaintance with and philosophical method of treating or preventing the other. No inconsiderable part of our present knowledge of the vital phenomena * Frankland, Journ. Chem. Soc. xix, p. 392. induced in the human economy in passing from cold to warm regions, or the reverse, is derived from experiments carried out in artificially made or seldom encountered climates. By hot-air chambers we illustrate the effects of augmented temperature on the respiration, pulse, &c., and by the rarefied atmosphere of mountain-tops show how diminished density acts. Neither of these, however, are fair examples of natural climates. Thus the former, dry and warm, is unlike the tropics, with its triple combination of increased heat, rarefied air, and excessive moisture; as the latter, dry and chilly, is dissimilar from the usual surface-climates of extra-tropical latitudes, which conjoin cold, condensation, and moisture. The dry and warm, or dry and cold, climates which occur in nature are usually local and limited. Nor do such abrupt and temporary exposures to heat and cold have any parallel in ordinary life, or are they likely to induce results similar to the comparatively slow transition involved in an ordinary change of climate; and though the rarefied air of heated chambers will decrease, while that of great altitudes will accelerate respiration, the former will do so less, and the latter more, than they otherwise would, from the skin, and especially the more slowly acting liver and kidneys, being unable at once to increase their action so as to aid the lungs in eliminating carbon. The functional changes so induced cannot therefore be taken as a fair criterion of what occurs in nature; and as mere approximates to truth, such observations, though interesting, are evidently wanting in practical importance. I. The Influence of Tropical Climates on the Respiration. It has been ascertained, by the experiments already alluded to, that the respirations are diminished in frequency in warm and increased in cold air; but we do not yet know what happens in the tropics, where great heat, rarity of air, and moisture are conjoined. Nor has it yet been shown whether the quantity of air respired is greater in the tropics or less. It is obviously necessary to ascertain both before we can decide whether the total quantity of air and oxygen respired, and the amount of carbonic acid and watery vapour exhaled, be different or not. The following experiment will show that the capacity of the chest for air is materially affected by tropical climates : |