57 lbs., and the consumption of solid carbon 12 lbs. The calorific power of the gases obtained by burning, under similar circumstances, 72 lbs. of dry air, without the addition of the heated steam, may be theoretically represented by 2,-the consumption of solid carbon being also, in this case, 12 lbs. ; the gases consist of 4 volumes of carbonic oxide, and 8 volumes of nitrogen-total 12 volumes. The ratios of combustible to that of incom potassium, a decilitre is evaporated as above to dryness, and the residue weighed; two grms. of this are then heated to redness, when the cyanide of potassium, chloride of potassium, and carbonate of potash fuse, while the cyanide of silver is converted into paracyanide of silver, and is subsequently entirely reduced. After 15 to 20 minutes' ignition, the cold mass is exhausted with water, and the silver remains in the crucible as a spongy mass, so that none is washed away by the water; it is then heated to red-bustible gasses are as one to two, either by ness, and weighed. Clay crucibles cannot be weight or volume, and the total weight is employed in determining the silver, as their 84lbs. porous mass imbibes a portion of the fused salt, and so produces a loss in silver. ON CERTAIN IMPROVEMENTS IN THE PRODUCTION OF COMBUSTIBLE GASES, AND THE APPLICATION OF THE SAME AS FUEL.* BY MR. W. POLLARD. THIS invention consists, firstly, in applying a blast of highly heated steam, in conjunction with atmospheric air, to convert solid fuel into combustible gases in appropriate furnaces, which gases are conveyed away by suitable flues or pipes to any place where they may be required to be burned; and, secondly, in burning the said combustible gases with a blast of hot air, to produce heat for all purposes for which solid fuel has hitherto been employed. The patentee remarks, that he is aware carbonic oxide gas has been frequently employed as fuel, but by his invention the mixture of carbonic oxide and hydrogen (obtained by a combined blast of highly heated steam and atmospheric air, acting on ignited fuel in excess as aforesaid), will consist, as nearly as possible, of one equivalent of hydrogen, and two equivalents of carbonic oxide, accompanied by the corresponding equivalents of nitrogen gas. To demonstrate the superior value, as fuel, of the mixture of hydrogen and carbonic oxide, as aforesaid, over carbonic oxide alone, it is sufficient to state the following facts: -The calorific power of the gases obtained by burning 36 lbs. of dry air, and 9 lbs. of heated steam, in an excess of ignited fuel, may be represented theoretically by 3, -they consist of 4 volumes of carbonic oxide, 2 volumes of hydrogen, and 4 volumes of nitrogen-in all 10 volumes; of which the proportions of the combustible are to the incombustible gases as 6 to 4, and if taken by weight as 29 to 28, the total weight being *Newton's Repertory of Arts. When equal weights of the two gases are compared, the theoretical calorific powers of each are as 221 to 100, but in practice the useful effect is much more in favor of the mixed carbonic oxide and hydrogen, especially when a high temperature is required. In these calculations no notice is taken of fractional parts, nor of the volatile matters contained in the fuel burned, as they do not alter the economical results. The advantages of employing the combustible gases produced in the manner above mentioned, as fuel, are thus stated :-First. Effectually preventing the smoke nuisance. Second. The power of regulating the temperature in metallurgical and other manufacturing operations in reverberatory furnaces, with a precision extremely difficult to obtain by the usual methods with solid fuel. By varying the proportions of hot air, and of the combustible gases, the heat can be raised or lowered in a moment, and the flame rendered oxidating, or reducing, or neuter, with the facility attending blow-pipe operations on a small scale. The advantages attending such an arrangement will immediately strike any one accustomed to these matters. Third. A complete command over the caloric, and over the volatile gaseous products generated by combustion. When we reflect on the very small proportion of the total heat produced, which can be, or is, utilized in reverberatories depending on common fire-places and chimney draft, the superiority of the gas reverberatories is immediately apparent. In the latter, worked by a blast or artificial current of air, the totality of the heat generated by combustion can be applied to useful purposes in general; the waste caloric will be most effectually expended in heating the air for burning the gas, but there are many other obvious ways of employing it. Fourth. In gas furnaces the necessity of high and expensive chimneys is completely done away with. Fifth. The complete command over the volatile and gaseous products of combustion is of great importance in many metallurgical operations, such as in smelting copper, tin, lead, &c. A nuisance hitherto inseparable from these operations may thus be obviated, and many valuable substances, hitherto wasted, may be turned to useful account. Sixth. The most inferior kinds of fuel, even such as can scarcely be used for any practical purpose in their natural or solid state may be employed to produce valuable combustible gases, in the manner above set forth. To conclude: after making ample allowance for the costs of generating and heating the steam, of blowing and heating the air, the original costs, and wear and tear of apparatus, &c., it will be found that an enormous saving will be effected by the application of gas fuel generally in metallurgical and manufacturing operations, for heating steam-boilers, and for almost every other purpose for which solid fuel has hitherto been used. For generating the gases, the patentee prefers to employ a furnace upon the plan used in smelting iron ores, with a fuelchamber above the boshes of a sufficient height to secure the perfect decomposition of carbonic acid. The furnace should, besides, be provided with close covers or slides, at the charging-plate, and with lateral flues and pipes to convey the combustible gases to their destination. It is advisable to use a proper flux to convert the earthy parts of the fuel into a fusible slag, which may be run off as formed, or tapped periodically, as may be found, most convenient; open burning fuel, or a mixture of open burning and caking fuel, is more convenient for generating gas than the very bituminous caking sorts; when the latter are used, it might be advisable to employ a stirring apparatus to facilitate the descent of the charges. To produce the blast, the patentee prefers using steam, at a pressure of from two to three atmospheres. After leaving the boiler, it passes through a common heating apparatus of iron pipes, in which it is heated from 570° to 600° Fahrenheit, or upwards; the steam-pipe is contracted considerably at the jet, which may be made to terminate at or within the mouth of a common open tuyer or tuyers, or be inserted within a closed hotair tuyer, and, pointing towards the nozzle, the blast of steam will always draw after it a sufficient proportion of air to affect a perfect combustion of the fuel. Hot air is not indispensable, for with cold air the operation succeeds perfectly; but either hot or cold air may be used. The dimensions of the apparatus will of course vary according to the quantity of solid fuel required to be converted into gases: one gas generator may serve to supply several gas furnaces. The mode of applying the combustible gases as fuel, and the construction of furnaces, may be varied considerably, according to circumstances; the only thing to be particularly attended to is, to arrange the jets or orifices for the issuing currents of combustible gases and hot air in such a manner, that the mixture of the two shall be as complete as possible, and the combustion be effected at that part of the furnace, where it will produce the most powerful effect. After the flame has done its office in one part of the furnace, it enters an oven, or wide flue, and heats the air-pipes placed therein. Cold air is blown in at the top, and in descending the circumvolutions of the pipes it becomes gradually heated to the degree required; the hot air is conducted, in suitable pipes to the point where the gas jets are situated, and the mixture is there inflamed. Both the gas and air-pipes are provided with throttlevalves or cocks, by which the quantities may be regulated at pleasure. All these matters being well understood, and daily practised with combustible gases obtained from iron furnaces, it will not be necessary to enter into more minute details on the subject. The patentee, in conclusion, states, that he does not claim, as new, the employment of carbonic oxide gas as fuel; but that which he does claim is the employment of a mixture of carbonic oxide gas and hydrogen, obtained by means of a combined blast of highly-heated steam and atmospheric air, acting on ignited fuel in excess, as above described. III. PHARMACY, MATERIA MEDICA, THERAPEUTICS, &c. A LENS composed of many pieces, one metre in diameter, constructed by M. Henry Lepante, and intended for a meteorological observatory at Vesuvius, has just reached me. To study, without danger, the adjustment of the different rings, as well as the distance and extent of the focus, I exposed this beautiful optical instrument to a clear moonlight, I brought the lens, by means of the double rotatory motion of which it is susceptible, to a plane exactly perpendicular to the direction of the rays: the light that fell on the surface of the lens was concentrated at the distance of about one metre, on a circular spot of the diameter of one centimetre. This little circle, extremely brilliant and clearly defined, of a size equal to the section of the tubes of my thermoscopic piles, suggested to me the idea of trying its action on these piles. The preparations for performing this experiment were immediately made, and a considerable deviation was seen, on the multiplying rheometer, as soon as the rays, penetrating the interior of the tube, fell on the anterior face of the apparatus. Astonished at the quickness of the action, and having some doubt whether it arose from the lunar heat, I placed my hand at a short distance from the front of the opening, and the index of the rheometer immediately returned to zero, passed it, and deviated in a contrary direction-an evident proof that its primitive movement was derived from frigorific radiation, that is to say, from a lowering of the temperature on the face of the pile exposed to the focus. The origin of this cold was easily seen. case, As the lens was on an open balcony, and beneath a perfectly clear sky, it ought, on account of the great emissive power of glass, to have radiated its heat into space, and thus reduce the temperature below that of the pile, which was enclosed in its metallic and placed in the interior of the apartment. As long as the pile was protected by its metal covering, the feeble radiation of the latter did not allow it to feel the influence of the cold of the lens, but, as soon as the covering was lowered, the calorific exchange took place between the two bodies, and the pile, losing more than it received, necessarily lowered the temperature of the exposed surface, and thus produced the electric current which caused the deviation of the needle of the rheometer. To remedy this inconvenience, I moved the lens within the window, that overlooked the balcony; and I applied a mat to the window, that could be easily raised to allow the lunar rays to enter the room, or lowered to intercept them. I kept the mat lowered until the equilibrium of the temperature was re-established; and after having satisfied myself that the rheometer underwent no deviation, when the covering of the pile was lowered, which always remained at the focus of the lens, I allowed the light of the moon to fall upon the instrument; a deviation of a few degrees of increased temperature manifested itself. I immediately repeated the experiment, and to my great surprise the deviation was in the opposite direction! A few moments' reflection were sufficient to convince me that these changes of direction depended, in all probability, on the gusts of external air that from time to time entered the room, and fell upon the uncovered surface of the thermoscopic body. It was easy to dispose matters in such a manner that the air could not have access behind the lens, but, guided by the theory of the identity of heat, light, and the well known experiment of Saussure with respect to a thermometer. placed below a broken window, I imagined we might succeed better by introducing into the interior of the tube two diaphragms of glass, perfectly diaphanous, and well polished on the four faces; the first, at a little distance from the pile, the second close to the opening. I therefore fitted up the tubes of my pile in this manner, and on the first favourable opportunity, I repeated the experiment. The index of the apparatus remained, at first, stationary for a few instants, then it began slowly to deviate, and after four or five minutes it stopped decidedly on an arc of 3.7. I withdrew the pile from the focus, and placed it on one side, its opening being still turned towards the centre of the lens; the deviation began immediately to diminish, and in a few minutes the index returned to zero. I frequently repeated the same operation, removing the pile sometimes on one side, sometimes on the other, and the needle always deviated when at the focus, and fell back to zero, when not in that position. Thus the direction of the deviation corresponded with that of the calorific action. The experiment was, therefore, perfectly satisfactory, and could not leave the shadow of a doubt. In fact, I had an opportunity of repeating it afterwards in the presence of M. Belli, professor of philosophy at the University of Pavia, and Messrs. Mossotti and Lavagna, of the University of Pisa, and many other distinguished philosophers, who all left my apartment perfectly convinced that the light of the moon is calorific. When I consider that the philosophers who attempted to discover the lunar heat during the last century employed, according to Laland, lenses of from one metre to 1m, 33c. in diameter, and Amonton's extremely sensitive thermoscope, I strongly suspect that the negative results described by these philosophers, depended, to a great extent, on the cold produced by their lenses, by celestial radiation in conjunction with the reduction of temperature caused by the movements of the external air, to which their instruments were exposed; so that I do not despair of being able to make the phenomenon apparent, with thermoscopes of ordinary power. Two children-a boy, aged five years, and a girl, three years of age-were each given a powder containing about ten grains of tartar emetic, mixed with a little sugar. The boy died about eight hours afterwards; the girl lived for four or five hours longer. Mr. Newman and myself were ordered by the coroner to make the necessary examinations of the bodies; this we did about one hundred and eleven hours after the death of the first child, whose body we found not at all emaciated, or presenting any external signs of disease. The abdomen was not distended. On opening the thorax, there was a slight adhesion of the left pleura, and about three drachms of serum were found in the right pleura. The anterior surface of the lungs In the meantime, by the employment of appeared healthy; the posterior surface more the present means of observation, I have red than usual, particularly at the lower lobe been able to satisfy myself, that the calorific of the right lung; heart natural; there was action of the moon varies, as we might easily a little dark blood in the right ventricle; the foresee, not only with its age, but also accorcoronary vessels were very fully injected. In ding to the height of this celestial body the abdomen, we found the liver healthy, the above the horizon. A trifling deviation of gall-bladder empty, the peritoneal coat of the plane of the lens from its normal direc- the intestines injected, evidently from recent tion, with respect to the rays also, consider-inflammation. The stomach and its contents ably diminishes the effect. Under these different circumstances, I have met with deviations which have varied from 0° 6 to 4°.8. The action through the glasses is so gradual that the index of the apparatus moves with admirable regularity, and without the least oscillation, whether in moving from its point of equilibrium, when the thermoscopic body is placed in the focus of the lens, or in returning, when we have scarcely moved it out of the focus, but always keeping it facing the lens. When performed under different lunations, the experiment has always succeeded, that is, the result has been always more or less decided, but in every case indicating an increase of temperature, I shall, therefore, repeat, that the fact of the existence of heat in the moon's radiation is perfectly certain, all that remains is to measure this calorific action, and to ascertain-1. What is its amount in thermometrical degrees. 2. What is its proportion to the solar heat? I shall endeavour to resolve these two great questions; but, with respect to the last, under what degree of approximation ought we to N.S., VOL. IV. were removed. The mucous membrane of the duodenum was inflamed, and covered with a whitish-yellow viscid secretion; this was observed throughout the intestinal canal, though more yellow in the colon and rectum; there was no ulceration. The other abdominal viscera were healthy, and presented no abnormal appearance. The jaws were so firmly set, that there was great difficulty in opening the mouth. The tongue was covered with a white fur, and appeared soddened; the fauces were not inflamed; the trachea and oesophagus had a natural appearance. On opening the cranium, the dura mater was found very vascular; the longitudinal sinus contained a coagulum of lymph, but very little blood; the vessels on the surface of the brain were very much injected with dark blood, the whole surface having a deep purple appearance. Every portion of the brain, when cut into, presented many bloody points; the cerebellum and medulla oblongata were also extremely vascular; there was no * Lancet. 2 F effusion in the ventricles or at the base of the brain. The stomach (the peritoneal coat of which was inflamed) contained about two ounces and a half of dark grumous fluid, but it was not distended with gas. On opening this viscus, the mucous membrane was found very much inflamed about the larger curvature, also at the cardiac orifice; there was no ulceration; the contents were very adherent to it, and in one place was a patch of lymph. On testing the contents, there was a slight acid reaction; but no test that was used indicated the presence of any antimony although the same tests applied to a mixture of one part of solution of tartarized antimony, and two of distilled water, displayed the characteristic appearances. In the other child, the morbid appearances were similar, though not to the same extent; there were also patches resembling the erup. tion of scarlatina on the arms, legs, and neck. The arachnoid membrane was more opaque than usual; and on the mucous membrane of the stomach, where the inflammation was greatest, were two or three white spots, each about the size of a split pea, and which, with the aid of a magnifying glass, appeared to be the commencement of ulceration. I did not see either of the children before death, but I ascertained from the relatives, that about twenty minutes after taking the powders, they had been seized with violent vomiting, and purging, and great prostration of strength, followed by convulsions and tetanic spasms. Mr. Newman, who was called in after the death of the first child, found the little girl had a remarkable distortion of countenance, with strabismus, violent convulsions of the limbs, and a peculiar tetanic spasm of the jaws, as though she was endeavouring to bite anything within reach; there was also great thirst, and extreme prostration of strength. The children were said to have been in good health till the morning on which the powders were taken, when they complained of pain in the back, and headache, for which symptoms the mother had usually adminis. tered emetics. THE ALKALOID SALTS, AND THEIR BY MESSRS. T. AND H. SMITH, EDINBURGH. IT has often occurred to us, that a great deal of error exists among medical men, and that their ideas are exceedingly vague, regarding * Lancet. the effects of the action of medicines produced by peculiar states of combination, but more especially in the case of the more active vegetable alkalis. For instance: when a salt of morphia is used, one person prefers a muriate, another a sulphate, and a third thinks that an acetate can alone secure the desired effects of the drug, unaccompanied by the idiosyncratic or disagreeable aftereffects, so apt to occur in some constitutions. We think, that the most proper way to arrive at a clear understanding, of the real influence caused by the acid in a powerful vegetable salt-say an acetate, or sulphate of morphia-is to take into account the equivalents of its proximate constituents. Let us, for example, take the muriate of morphia. The equivalent of morphia itself, like most of the active alkaloids, is very high, being close upon 300. The equivalent of muriatic acid is only 37, being about a tenth of the equivalent of muriate of morphia; and, as the medium dose of this last is only about the eighth of a grain, a single dose can only contain about the 80th of a grain of muriatic acid. As the equivalent of acetic acid is 51, and that of sulphuric acid 40, the argument applies with equal force to sulphates and acetates. Now is it not un reasonable, and as much an outrage upon common sense, as the wild doctrines of ho mœopathy, to suppose for one moment that it can be of the least possible consequence to the patient whether the salt given be an acetate, a muriate, or a salt of any acid whatever? It may be said, that, by the combination, a peculiar change is produced, analogous to what occurs when a strong mineral acid is neutralized by an alkali, where the characters of both constituents are destroyed, and a new substance, possessing entirely new properties, produced. We do not think this is the case, in so far as medicinal action is concerned. We do not know a single fact sufficiently strong to give the least countenance to such an opinion. The only result, we conceive, that can take place, by combining the alkaloid with an acid, is to obviate any impediment to its complete and quick action on the nervous into contact. or absorbing surface with which it is brought It is certain, that in the case of acetate of morphia, where perhaps this preference has been more shown, and the propriety of which has been less called in question than in any other instance, there must be some fallacy in the circumstances supposed to prove its superiority over the muriate; for there can hardly fail to be as much muriatic acid in the stomach, in the greater number of cases, as would be suffi |