CHEMICAL NEWS, July 28, 1876. Measuring Air in Mines. in reading off the velocity from such the average of the vibrations must be taken. But with the windmill anemometers the altered speeds are more difficult to detect, and they are also accompanied by the serious defect that when the intermittence is great the number of revolutions recorded are so largely in excess as to be practically useless, owing to the momentum which the wheel attains, when the current is quick, carrying it (especially when the wheel is a heavy one) with but slightly lessened speed through the periods when the current is slow. This exaggeration of the revolutions of wheel anemometers in intermitting currents may be readily proved, either by watching the instrument when blown upon in puffs, or by passing it intermittingly over any given distance in a still atmosphere. It may also be proved by placing the instrument in an intermitting current, when the actual average velocity can be accurately known, as in those cases where the total quantity of air passing is known by having to pass through an air-pump of certain dimensions, and making a certain number of strokes per minute. When furnaces or fans are used as the ventilating power, the intermittence is generally not of much importance, except when air doors are opened and such like, or when firing up the furnace, or if there be some irregularity in the construction or working of the fan. But with a single air-pump, worked with one piston, or if there be two pumps and two pistons, but changing stroke at the same time, the effect upon the anemometer, caused by the intermitting current, is such that the revolutions are enormously increased." The intermittence is even perceptible, and affects the anemometer when there are two pumps, one of which changes stroke when the other is at half stroke, but this greatly lessens the injurious effect, and the current is comparatively steady. 37 n being the number of revolutions indicated by the anemometer, and a and b are two coefficient constant numbers determined by the series of experiments, and v the true velocity of the air. This formula is still used, except that other letters are now more common. This whirling machine of M. Combes was probably the first of the kind. On seeing it, I saw at once that the principle was good, but that the mode of carrying it into practice might be improved; and having described it to Mr. Casartelli, of Manchester, he constructed an improved machine, which was fixed on the floor, and with a whirling circle of about 25 feet in circumference, that of M. Combes being much smaller. Improving upon this some time afterwards, Mr. John Daglish, then viewer at the Hetton Colliery, in Durham, in conjunction, I think, with Mr. Lindsay Wood, adapted to a machine, on the same principle, a weight by which steady velocity was given, the speeds being varied according to the increased or decreased weight attached at one time. And this is the whirling machine now used by instrument makers for setting the scale on the quadrant of the Dickinson anemometer, and for ascertaining the correction for bringing revolutions into velocities with the windmill anemometers. When, however, a standard anemometer of either kind has been obtained, it may be used for setting and testing other anemometers by, provided that the two be carefully experimented upon together in the same currents of air. Instead of using the formula for deducing the velocity from the revolutions of windmill anemometers, the correction is now frequently, and indeed more readily, made simply by adding a number, which, by, testing, as previously described, is found applicable to the particular instrument at different velocities. Thus, if it requires a current of say 50 feet per minute before the wheel begins to revolve, it would require an addition of that number to ascertain the velocity of the air when the anemometer just begins to move, and so on, varying with the respective velocities and instruments. For making the correction in this way, the numbers to be added are sometimes given in a tabular form, and sometimes in the form of a diagram, from which the number has to be measured by a scale. The correction, as before stated, varies with each anemometer; but with Biram anemometers of like construction, and registering revolutions without any attempted correction in the instrument, the required addition for correction does not vary much, and it would appear that, with instruments so constructed, the correcting number to be added diminishes as the velocity increases, the number being often small when the revolutions exceed 400 per minute. The ratio of correction appearing, generally, like the asymptote of the hyperbola, always approaching, but never meeting. Similarly exaggerated results also occur with the windmill anemometers when they are changed about at short intervals, as is not uncommon, in endeavouring to get an average velocity of the current in the various parts of the space where the observation is being taken. In these instances the momentum attained in the quick part of the current carries the wheel round at a higher velocity than it would have attained in those parts where the current is slow. Inaccuracy in this latter respect may, however, be avoided by having separate anemometers placed at the same time in each part of the airway space where the velocity varies, and averaging the results. When, however, only one anemometer is used for measuring a current which varies at different parts of the space where the velocity is being taken, the anemometer should either be held for a long time in each part of the space, so as to minimise the effect caused by the momentum of the wheel, or a separate measurement should be made of the respective velocities, and an average taken of the results. But in this way it will have to be assumed that the current continued uniform whilst the respective observations were being taken, which perhaps may not have been the fact. The space occupied by the operator's body in using any anemometer, especially in small airways, or if the instrument be not properly faced to the current, may also, obviously, render the result inaccurate. It is also essential in using windmill anemometers to ascertain the proportion existing in each instrument between the number of revolutions and the velocity of the air-current. In M. Combes's treatise, previously named, the whirling machine by which he made experiments to find this correction is described. I had an opportunity of seeing this whirling machine at the instrument maker's (M. Newman, I think) when in Paris, in 1853. It consisted simply of a balanced rod, on one end of which the anemometer was placed, and being held overhead by one hand and twirled round on a spindle by the other hand. By taking a series of observations at different speeds over certain linear distances, in a still atmosphere, and comparing the number of revolutions which the anemometer From these sources of error in the measurement of air currents in mines many mistakes have apparently been made in the amounts of ventilation, and when the result has been used for determining the amount of power utilised by ventilating machines, the percentage has been greatly exaggerated. For comparative observations of the ventilation made from time to time in a mine, the surest way is to place the same anemometer on the same spot, and under the same circumstances, on each occasion relying upon revolutions and not velocity. But for ascertaining the actual quantity of air passing in a mine when the current is intermitting-so difficult, indeed almost insurmountable, is the process with an anemometer-that, where open lights are allowed, it seems preferable (although it has been called a barbarous way) to resort to the old rough and ready ways, by the smoke of gunpowder or tobacco, or by the flame of a candle, as previously described; and where gunpowder, smoking, and open lights are prohibited, a small balloon filled with gas, to float in the air and bound about from roof to floor and side to side, as carried by the air current, is a good substitute. For steady currents, however, there is nothing so good as an anemometer. The candle cannot be carried with the average of the whole current, and the smoke of powder or tobacco is found to hang where the current is slow, making it at times uncertain what portion of the arrival should be taken as indicating the average. NOTICES OF BOOKS. Analysts' Annual Note-Book, 1875. Edited by SIDNEY W⚫ RICH. London: Published for the Author. Similarly erroneous computations of the percentage of power utilised by ventilating machines have likewise been made, when, in intermitting currents, the pressure of air (which is one factor in the calculation) has been taken by the common inverted glass syphon water-gauge. Not-well as the authorship of his extracts. We must likewise withstanding that in nearly all such gauges the tube is usually contracted at the bend, the water dances up and down so that it is impossible to read off accurately the average distance between the two surfaces. The want of a compensating water-gauge for measuring the pressure of intermitting currents first presented itself to me in the year 1861, when measuring the amount of power utilised by the Struvé air pumps. On that occasion, finding it impossible to obtain any reliable measure of the average pressure of air by the ordinary water-gauge, my colleagues, Mr. Thomas Evans and the late Mr. John Job Atkinson, and myself, used two ordinary buckets of water, one bucket being placed outside and the other in the return air, the water in each being connected by an india-rubber tube. This method served the purpose, but as the buckets widened towards the top, the area of the surface of water in each was not equal, and consequently the depression of water in one did not correspond exactly with the elevation in the other, which made it requisite to measure the height it rose in one and the depth it fell in the other, and to add the two together in order to obtain the total pressure. A readier mode than the buckets of water, as might be expected, soon occurred to us, and in the same year I had a proper compensating water-gauge, made by Mr. Casartelli, of Manchester, (the one shown to the meeting) by which, no matter how intermitting the current, an accurate measure of the pressure may be readily taken, by having the two limbs for the water so large and the connecting aperture at the bottom so small that the flow of water does not sensibly affect the level during the pulsations. The gauge consists of a brass box, divided by a thin partition into two chambers, with glass front, and with the aperture at the bottom connecting the water in the two chambers regulated by a tap. The full size of the gauge is 6 inches high, 4 inches broad, and 3 inches wide; the 4 inches in breadth being divided by the partition, making the two chambers each 2 by 3 by 6 inches. The tap for regulating the flow of water between the two chambers is worked outside, underneath the bottom of the gauge. At the top of one of the chambers there is an opening 1 inch in area to admit the pressure of air on that side, and at the top of the other chamber there is a brass nozzle for inserting through an augur hole to admit the pressure of air at the other side. There is also a tap on this nozzle for closing when required. At each side of the glass front, and also down the middle of it in front of the partition dividing the two chambers, there are scales graduated into inches and tenths, so that the difference between the level of the water in the two chambers may be accurately seen. Mr. Atkinson soon afterwards had also a gauge of the same kind made for himself, but his had a pipe which came outside for connecting the two chambers at the bottom, instead of a tap regulating the size of a hole in the partition, as in mine. These two compensating water-gauges were probably the first of the kind used in this country; but on afterwards using them in testing some of the ventilating machines in Belgium, we were informed that similar gauges had been previously used by the ingenious mining engineers in that country. THIS book, as its title implies, consists of a selection of analytical methods which have appeared during the past year. The name of the author is given in every case, but there is, in most instances at least, nothing to indicate whether the various papers are reprints from scientific journals and from the Transactions of societies, or whether they have been originally communicated to the "Analysts' Annual Note-Book." We cannot help suggesting that in future issues of this note-book the editor would do well to conform to the custom of indicating the source as insist on the danger of abridging the descriptions of analytical processes. To take an instance: in MM. Champion and Pellet's method for determining glucose in presence of sugar Mr. Rich tells us to "collect and wash the suboxide (copper) formed, place the filter, still damp, in a capsule, and add dilute hydrochloric acid, which converts the suboxide of copper into sub-chloride. The liquid becomes coloured and the copper passes into the state of bichloride of copper of a greenish yellow colour when it is titrated with chloride of tin." But if we refer to the Comptes Rendus, No. 3, Jan. 18, 1875, or, in default, the CHEMICAL NEWs, vol. xxxi., p. 84, we shall find that the liquid in question is to be "raised to a boil, adding by degrees some crystals of chlorate of potash," by the action of which the conversion of the sub-chloride of copper into the bichloride is effected. If, as we doubt not, Mr. Rich wishes to render his note-book really useful to analysts, he will agree with us that every step in a novel analytical method should be fully described. A great part of the matter given relates to the adulteration of food and drugs, and must have already come under the notice of the majority of chemists in this country. The fact that certain impure ammonia turns a "gooseberry red colour" on admixture with nitric acid is not a recent observation. To our certain knowledge it was utilised as a test in dye-works, &c., in the North of England eight years ago. WE have here a most elaborate report on the sanitary condition of the State of Massachusetts. The condition of the rivers, the sources of pollution, the water supply for domestic and manufacturing uses, the sewerage of the towns and villages, and the disposal of the sewage are all fully described. In On the subject of the "Disposal of Sewage" there is a special paper by Dr. C. F. Folsom, in which the past experience of the principal European countries is described. Such a treatise would have been exceedingly useful had the author taken the trouble to ascertain the truth. stead of so doing he accepts and retails a number of the statements which English sewage irrigationists have repeated till they believe them. As an instance of the glaring errors with which this essay abounds we turn to the account of the sewage treatment at Leeds. We are told that the authorities there tried several of the precipitating processes one after the other, "finding them all failures." This is incorrect; two, if not three, of the processes tried have been found successful, and one of these has been selected as most completely answering all the conditions required of a sewage process. The deposit is not, as Dr. Folsom has been informed, "quite offensive" whilst drying. The tanks are not made of iron, but of masonry; they are not six in number, but twelve they are not cleaned out when the deposit becomes a foot deep-which is never the case in those farthest from the infall-but pro re nata. The effluent when the opera CHEMICAL NEWS,) Organisation among Chemists. 39 I have already given him a capital reference and regret to find that he cannot, or will not, avail himself of it. But perhaps I had better reply to his questions, though I am afraid that will not help him much. 1. How does Dr. Phipson know that the 6.20 per cent of Mn2O3 was not made up of 3:41 MnO2 and 2.79 MnO? Answer. Because there is no MnO in the sample. 2. If he does not know how, &c.? Answer. He does know. tion is fairly worked does not "soon putrefy." The | Mn2O3, &c., which he ought to be able to answer himself. manure, instead of being unable to find a sale at two shillings a ton, is contracted for a twelvemonth in advance at twelve. What confidence can be placed in an author who heaps up inaccuracy upon inaccuracy in such a manner, and what must we think of his informants? One truthful confession, however, somewhat redeems this imaginative description of the Leeds Sewage Works. The author admits the absence of offensive smell. Here he contradicts one of the most preposterous assertions of the Rivers' Pollution Commission that "bad smells are always perceptible." What he admits further negatives another of their baseless statements, that "the process produces no clearer water than what would have resulted if the sewage were allowed to settle by itself." It so happens that this point has been experimentally decided at Leeds. Some years ago, we do not know whether, in consequence of the assertion quoted by Dr. Folsom-a tank at the Old Works was filled with sewage and allowed to settle. The result was not a clear, colourless, inodorous liquid like that attainable by precipitation, but a nuisance which no one could approach without feeling nauseated. Speaking of Leamington the author declares that "in 1870 the authorities of this town, having proved the precipitation processes to be costly and expensive failures, gave up their tanks and made a contract to deliver their sewage upon Heathcote Farm belonging to the Earl of Warwick." The only processes which we have ever heard of as having been used at Leamington were the "lime" and the "A B C." The latter of these was not tried until after the contract had been made with Lord Warwick. Consequently it was a mere interim arrangement and not a "costly and expensive" failure which drove the Leamington authorities to irrigation. It is not too much to say that every part of Dr. Folsom's treatise teems with errors. His notice of sewage irrigation is as one-sidely favourable, as his remarks on precipitation processes are unjustly condemnatory. No mention is made of the important results obtained by Mr. Smee, jun., who showed that milk and butter obtained from cows fed on sewage grass became more rapidly offensive than that of cows fed upon normal herbage. No notice is taken of the important evidence of Mr. Markham that irrigation, even with common river water and applied only when necessitated by dry weather, injures the health of the surrounding districts in India. No less has Dr. Folsom left out of account the valuable report of M. Lefeldt, the Prussian commissioner, who complains of the "mephitic odours" on the model sewage farm, and who found the stems of grass from irrigated meadows full of unassimilated sewage matters. Irrigation is doubtless valuable in climates where there is no rain during half the year, but in England where the average supply of moisture is too great for our most valuable crops it is a delusion which it will puzzle posterity to account for. In short, we must pronounce Dr. Folsom's treatise an utterly untrustworthy compilation, and for the sake of sanitary science in America we regret that it has ever appeared. The other portions of the volume are of much greater value. 3. What process was employed for the determination of the main quantity of MnO2, and would not that amount include the 3'41 per cent assuming the latter to have any existence? Answer.--No "main quantity" of MnO2 was determined. 4. If the result of the determination of MnO2 72:17 per cent represents the total quantity of that oxide present, must not the remainder of the Mn necessarily have existed as MnO and not as Mn2O3? Answer. Certainly not (vide answer to question 1). 5. If the last question is answered in the affirmative has not Dr. Phipson counted his oxygen twice over? Answer. It is not answered in the affirmative. I am, &c., London, July 22, 1876. T. L. PHIPSON, Ph.D. To the Editor of the Chemical News. SIR,-The formation of an Institute of Professional Chemists has undoubtedly been mooted mainly for the of the proposed regulations in the scheme put forward by purpose of raising the status of the chemists; but some Mr. Pettengill's clients in the CHEMICAL NEWS of the 9th ult., do not by any means appear likely to further this end. For instance, a person would be eligible for membership if he had "practised on his own account in the Profession of a consulting or analytical chemist." This would obviously admit all those quacks who have chosen to dub themselves "Analytical and Consulting while at the same time many of the so-called "works' Chemists" without the faintest qualification for the work, chemists" who have had a thoroughly good scientific training with much experience in technological work, would, unless they had advertised themselves "Analytical and Consulting Chemists," be excluded. For the purpose of guiding in its action towards the proposed Institute, I am instructed by the Council of the Faraday Club (which consists solely of chemists of this district) to ask publicly of those engaged in forwarding the new scheme : as 1. How are "high" and "low" analysts and quacks in general now in practice to be excluded? 2. How will technology be represented on the Board of the proposed Institute ?-I am, &c., Pro the Council of the Faraday Club, Runcorn, July 21, 1876. 40 Chemical Notices from Foreign Sources. CHEMICAL NEWS, CHEMICAL NOTICES FROM FOREIGN the Department of l'Herault, as pointed out by N. Thomas SOURCES. NOTE.-All degrees of temperature are Centigrade, unless otherwise expressed. (Comptes Rendus, May 8). Influence of Temperature upon Magnetisation.— M. J. M. Gaugain.-Not adapted for abstraction. Extension of the Principle of Carnot to the Theory of Electrical Phenomena : General Differential Equations of Equilibrium and of the Movement of any Reversible Electric System whatsoever.-M. G. Lippmann.-A mathematical paper, incapable of useful abstraction. Researches on the Commercial Analysis of Raw Sugars.-A. Riche and Ch. Bardy.-The chief novelty in the authors' method is that they take a sample five times larger than usual, and operate upon one-fifth of the solution, in order thus to obtain a fairly representative sample. They also employ a modification of the ordinary polarimetric tube. New Class of Colouring Matters.-M. Ch. Lauth.Reserved for insertion in full. Certain Derivatives of Isoxylene.-M. Ch. Gundelach.-This paper contains an account of the chloride of isotolyl and of isotoluic aldehyd. On Nitro-Alizarin.-M. A. Rosenstiehl.-The author Comptes Rendus Hebdomadaires des Seances, de l'Acadenie des Sciences. No. 25, June 19, 1876. Cause of the Movements in the Radiometer of Mr. Crookes.-M. Govi.-Fresnel had found, in 1825, that light bodies freely suspended in an ordinary vacuum Differential Actinometer.-M. N. Egoroff. — The might perform under the action of light or heat certain author describes his apparatus, with which he hopes to movements, which he referred to the thermic currents of determine the coefficients of absorption of the ultra-violet the rarefied gas contained in the receiver. These same rays. movements, obtained in a far more perfect vacuum, have been lately ascribed by Mr. Crookes to the impulsive force of the luminous rays. It is little probable that the displacement of a gas the pressure of which is reduced to a few hundredths of a m.m. can impress an appreciable motion on bodies whose mass is always relatively very large. As for the impulsive force of light, it ought to be nil if it be true that light and heat are merely vibratory movements of the ether or of the ultimate particles of bodies. It is no more possible for light to drive a body before it than for the sounds of a musical instrument to sweep along a feather or a particle of dust in the direction in which they are propagated. If the impulsive force of light were proved, it would be necessary to renounce the theory of The Nickel Ore of New Caledonia, or Garnierite. Huyghens; but before doing that we must at least exhaust-M. J. Garnier.-The nickel ores of New Caledonia are all possible means of explaining the movements studied by not arsenio-sulphides like those hitherto utilised, but siliFresnel and by Mr. Crookes. If the thermic currents of cates of nickel and magnesia. The ore is found amidst rarefied gases contained in the receiver where the movethe masses of serpentine very abundant in certain parts of ment is produced do not suffice for the explanation of the the island, and associated with euphotides, diorites, amfacts observed, there is another cause of displacement phibolites, &c. The nickel is accompanied by iron, chrome, much more efficacious, but hitherto not taken into account, and cobalt; these metals, especially the two former, are which may well give the true explanation of the pheno- of an unexampled abundance. The cobalt is associated mena. This cause is merely the dilation by heat, or the with manganese. contraction by cold, of the gaseous layers which all bodies retain on their surface, even when placed in an absolute vacuum. The mass of these gaseous strata is far from being insignificant relatively to that of the bodies which retain them, especially when they are in a very fine state of division, like lamp-black, platinum-black, &c.; or if they are endowed with an especial affinity for certain gases, as palladium for hydrogen. If we admit that this is the true explanation of the facts studied by Mr. Crookes, we may construct insensible radiometers by heating the immovable discs of the apparatus during the action of the mercurial pump. So long as we have not removed from the apparatus the source of movement just pointed out, it is needless to have recourse for the explanation of the phenomena to an impulsive force, which would be at variance with all that we know best concerning the nature of light. M. Fizeau gave an account of an experiment which does not seem favourable to the explanation given by Govi. If a series of equidistant candles are placed around a radiometer, forming a circle of about 50 centimetres in diameter, in the centre of which is the instrument, it is equally and symmetrically illuminated all around its axis of rotation, so that the discs whilst turning receive constantly the same quantity of light as well on their blackened as on their polished surfaces. The rotatory movement being established, under these conditions, with a speed of about ten revolutions in seven seconds, the number of rotations was carefally taken in each successive five minutes. The speed was found constant, and did not slacken during an entire hour. In these conditions would not the speed of the rotation diminish and cease at the expiration of a very short time it it was really produced by the liberation of condensed gases or vapours from the blackened surfaces? We cannot from the uniformity of the illumination admit the supposed alternations of condensation and emissions necessary for the continued maintenance of the movement. Existence of Mercury in the Cevennes.-M. Leymerie.-The author confirms the existence of mercury in demanded the opening of a sealed paper deposited by him on March 13, 1876, and containing an account of the new compound. Madder-red exposed to nitrous vapours bedered more brilliant by washing and by boiling soap-lyes. comes orange, and the shade thus produced is only renTurkey-red undergoes the same change, the resulting colour being quite as solid as that from which it is derived, and of a tone and a brightness which could hitherto only be produced on printed goods by means of chromate of lead. The orange obtained by the action of nitrous vapours is so much the brighter, as the madder-red contains less purpurin. The colour can scarcely be withdrawn from the fibre upon which it is deposited without attacking the latter. The small quantity obtained dyed an orange shade with mordants of alumina. Nitrous vapour brought in contact with alizarin in solution, or suspended in water, acetic acid, alcohol, sulphuric acid, &c., produced compounds of a yellow colour, but devoid of tinctorial power. This result agrees with that of Ntenhaus, who found that alizarin was reduced by nitrous acid to anthraquinon under circumstances very analogous. Fuming nitric acid employed alone, or mixed with sulphuric acid, did not give a satisfactory result. The author then prepared the new colour by pouring the commercial alizarin paste into large glass flasks, coating the interior therewith by means of agitation, draining, and drying, thus leaving the flasks lined with a layer of finely divided alizarin. They were then filled with nitrous vapours and stoppered, when in a few minutes the colour of the alizarin was changed, and the gas decolourised. Two colouring matters were formed, one of which, probably unchanged alizarin, gave a red with aluminous mordants, whilst the new substance dyed an orange. The new colour is composed of Carbon .. Nitrogen 58.94 .. 2'45 2.1 .. .. .. 4'91 CHEMICAL NEWS, July 28, 1876. Chemical Notices from Foreign Sources. 41 answering to the formula C14H7(NO2)04. By the reduc- | salt is decomposed. This solution is made by dissolving tion of nitralizarin the author has obtained two products, which are formed successively: the one dissolves in alkalies with a blue colour, and dyes a garnet with aluminous mordants; the other dissolves in alkalies with a brown colour, and dyes a catechu colour with alumina. Bulletin de la Societe Chimique de Paris, On Benzylic Naphthalin.-M. Pierre Miguel.-Not suitable for abstraction. Metallurgy of Silver in the Moist Way.-M. Antony Guyard (Hugo Tamm).-This paper is devoted to the treatment of the sulpho-antimoniuretted ores of Bolivia, known as Rossicler,—very rich, but so difficult to treat in the dry way that many smelters refuse to work them. They may, however, be very advantageously treated in the moist way, the sole condition of success being the use of a quantity of acid sufficient to oxidise the sulphur and all the metals. The following analyses show the general composition of these ores : Analysis of the Peroxide of Manganese.-Dr. T. L. Phipson.-Already noticed. Memoir on the Determination of Nitrates.-M. Ferd. Jean. For the analysis of commercial samples of nitre the author recommends the following procedure:Into a small glass flask, holding about 200 c.c., introduce a concentrated and very acid solution of ferrous chloride. The flask is closed with an india-rubber stopper pierced with a hole, through which pass a delivery tube under a leaden shelf in a tank of water lined with lead, and a very short tube, to which is fixed a small funnel by means of a flexible caoutchouc tube, the communication with the flask being intercepted by means of a Mohr's springclip or a small glass tap. The trough being filled with water, the ferrous chloride is raised to a boil, and, as soon as the sound made by the condensation of the acid on the water of the trough announces that' a vacuum has been made in the flask, a gas-jar filled with water is placed over the opening in the shelf. The jar should be of the capacity of 200 c.c., graduated in tenths. Then we pour into the funnel 5 c.c. of a solution of nitrate of soda, formed by dissolving in a litre of 66 grms. of pure nitrate of soda recently melted at a low temperature. The solution of ferrous chloride being kept at a boil, the solution of nitre is allowed to enter the flask drop by drop, taking care not to empty the funnel completely: 2 to 3 c.c. of distilled water are then placed in the funnel and allowed to enter the funnel, and finally the funnel and the tube are rinsed with to 10 c.c. of fuming hydrochloric acid. The binoxide of nitrogen produced by the decomposition of the nitrate of soda enters the graduated jar, and as soon as the sound announcing the presence of a vacuum in the flask is heard the graduated jar is withdrawn and allowed to stand on a support in the trough. This first operation makes known the volume of gas obtained from a known weight of nitre, without it being needful to take account of the corrections for temperature, pressure, &c. Into the flask are then introduced 5 c.c. of a solution of the nitre in question in 100 c.c. of distilled water, and the 66 grms. in the same manner as the foregoing, and the binoxide of nitrogen is collected in a second graduated jar. The two jars are kept till they have acquired the same temperature and the respective volumes of gas produced are read off, care being taken to keep them immersed so that the water may stand at the same level within and without. The volume of gas produced by a given weight being thus known, the proportion of real nitre existing in the sample under examination is readily calculated. (In a subsequent part of the paper the author speaks of the determination of nitrogen by the "procede Winckling." On careful examination this proves to be a Gallicised version of the name of Mr. Wanklyn.) On Isobutylenic Chlorhydrine, and on the Law of the Addition of Hypochlorous Acid.-M. L. Henry. -Already noticed. On the Law of Dulong and Petit.-M. A. Terreil. - Already noticed. On Erythrophlæum Guineense and couminga.MM. N. Gallois and E. Hardy.-A chemico-pharmaceutical paper, not adapted for abstraction. On Certain Derivatives of Isoxylene. - M. Ch. Gundelach.-Already noticed. Justus Liebig's Annalen der Chemie, Combination of the Elements of the Nitrogen Group with the Radicals of the Aromatic Series: Section I.; on Aromatic Phosphorus Compounds. -A. Michælis.-A treatise extending to one hundred pages, and utterly incapable of useful abstraction. On Ammonium Compounds.-W. Lossen.-Likewise not adapted for abstraction. On Benzhydroxamic-ethylester.- Dr. Martin E. Waldstein.-The author describes the properties of this compound, to which he assigns the formula and its silver salt, and then discusses its constitution, N(C-H5O) (C2H5)HO, with those of ethyl-benz-hydroxamic acid, benz-hydroxamic acid, and the benz-hydroxamates; the decomposition of benz-hydroxamic-ethylester by hydrochloric acid, and its methyl compound. Occurrence of Arsenic in Ancient Bronzes.-H. Spirgatis.-The author has found arsenic in old Prussian bronzes to the extent of 3.52 per cent. PATENTS. ABRIDGMENTS OF PROVISIONAL AND COMPLETE SPECIFICATIONS. Improvements in the manufacture of chlorine. H. Deacon, Appleton House, Widnes, Lancaster. March 11, 1875.-No. 906. This invention consists in using a mixture of common salt or other similar chloride with a compound or salt of copper, or with other so-called chemically active salt, uuch as is now employed in what is known as Deacon's process for making chlorine from hydrochloric acid gas and air, previously mixed and heated in combination with a separate source of hydrochloric acid gas, which may be from the well-known manufacture of sulphate of soda by reacting on common salt with sulphuric acid, or otherwise obtained. The common salt used in carrying out this invention may be in grains, which may either be moistened with a solution of the so-called chemically active salt or salts, which may, for example, be sulphate of copper; or the common salt and sulphate of copper may be in solution, and this solution may be used to impregnate pieces of burnt clay or other porous materials therewith, the mixture or impregnated material being subsequently dried. Or salt mixed with copper ore-such, for example, as the sulphurets or the oxides-or with other natural or artificially produced insoluble compounds of coppe:, may, in a fine state of division, be employed in lieu thereof, or in conjunction with the soluble salts of copper before referred to. The apparatus, in which the mixtures as described may be used in combination with a separate source of hydrochloric acid, may be a column or tower, or a number of columns or towers connected together, and made of iron or brickwork or both, as more fully described in the Specification of a Patent granted to me on September 13, 1870, No. 2469. During the manufacture of chlorine by this in |