Mott, chemist of the United States Indian Department, had occasion to analyze a number of baking-powders, and found that many of them contained alum and other injurious substances. The best baking-powders are, accord-. ing to Dr. Mott, composed of bitartrate of potash, tartaric acid, carbonate of ammonia, and soda bicarbonate, bound together by a little starch. Inferior baking-powders consist of alum and bicarbonate of soda, and often contain terra alba, insoluble phosphate of lime, etc. The physiological effect of alum taken internally is to produce dyspepsia, constipation, griping, and a host of other disorders of the alimentary tract; and though a person need not apprehend that such grave evils will at once ensue after eating bread "raised" by such powders, there is no doubt that the protracted use of such bread would produce the morbid conditions enumerated. In the tables which follow, Dr. Mott states the results of his own quantitative analysis of different baking-powders: No. 1.-A Baking-Powder made in New York. 26.45 per cent. 24.17 Burnt alum... Bicarbonate of soda.. 66 as follows: 1,000 grains of bread are burnt down to a small bulk, powdered with about 100 grain measures of hydric chloride, and warmed for a few minutes; about two ounces of water are then added, boiled for five minutes, filtered, etc. A solution containing about 250 grains of pure sodic hydrate is made in a very little water; and to this solution, when boiling, is very cautiously added the boiling acid solution of the charred bread, the whole boiled for a few minutes, filtered and washed. The filtrate, after the addition of a few drops of a concentrated solution of disodic phosphate, is slightly acidified with hydric chloride, and subsequently rendered just alkaline with ammonic hydrate and boiled. The precipitate is collected, washed, and weighed as aluminic phosphate. New Elements.-Although research appears to be tending toward a confirmation of the view that the elements are really compound, and that on further analysis they will be found to have striking points of resemblance if not actual identity, several so-called new ones have been added to the list during the year. Philippium was found as an oxide by Mr. Marc Delafontaine in a specimen of samarskite (an uranoniobate of yttrium and iron) from North Carolina. The earth of this metal (philippia) is yellow like terbia, but its equivalent is lower. In communicating to the Paris Academy of Sciences an account of his discovery, Mr. Delafontaine takes its approximate equivalent to be comprised between 90 and 95: Philippic formiate crystallizes with great facility, either on cooling or by spontaneous evaporation, in small, brilliant, rhomboidal prisms, less soluble than the formiate of yttria. The terbic formiate is anhydrous and soluble in from 30 to 35 parts of wa ter. The sodio-terbic sulphate dissolves with difficulty in a saturated solution of sodic sulphate, while the corresponding salt dissolves in it easily. In the spectroscope the concentrated solution of philippium gives in the indigo-blue a magnificent absorption band, very intense and rather broad, with well-defined edges. This band, which strikes one No. 4.—A Baking-Powder_manufactured in Mil. at a first glance, is not seen in solutions of terbium, waukee, Wis. Estimation of Alum in Bread.-The old Normandy or soda process for the estimation of alum in bread has long been out of use, on account of the great difficulty experienced in redissolving the aluminic hydrate or phosphate after its precipitation, which often led to inaccurate results. Other processes have been substituted, many of which are very complicated and unsatisfactory; and they are now likely to be displaced by a modification of the Normandy method, which simplifies the procedure and leaves little to be desired in point of accuracy. This consists in adding the boiling acid solution of the charred bread to a boiling solution of sodic hydrate, containing a large excess, yttrium, and erbium. It is, then, characteristic of philippium, and thus M. Soret's conjecture that it belongs to a new simple body is confirmed. In the green are seen two rather fine rays varying in intensity, the most refrangible of which belongs to erbium, as well as a faint ray in the blue near to the boundary of the green. The least refrangible of the green rays belongs perhaps to philippium; for, if in some specimens it has been less intense, others, on the contrary, show it to be nearly as powerful as the erbium ray. Lastly, in the red there is at least one fine ray which has not been identified. The same chemist reports the discovery of a second new element in the same mineral (samarskite), to which he has given the name of decipium. The oxide of decipium (assuming its formula to be DpO) has a molecular weight of 122. The nitrate gives an absorption spectrum consisting of at least three bands, in the blue and the indigo. The most refrangible of them is a little less broad than that of philippium, is dark, and corresponds in its center to 8 wave-length near 4,160. This distinguishes decipium from didymium and terbium. The second band is narrow, intense, not defined on its edges, and is in the less refrangible part of the blue, corresponding to a wave-length of 4,780. This is nearly the exact place of one of the didymium bands, but the latter is far less intense. Finally, nearly on the limit of the blue and green there is an appearance of the third band. Another new element is announced by Dr. J. Lawrence Smith, which he calls mosandrum; this, too, was found in samarskite. The earth (mosandra) of this metal belongs to the cerium group. Finally, Marignac has described some of the compounds of a new element found in gadolinite, and to which he gives the name of ytterbium. The atomic weight of 131 is provisionally adopted for this element. The nitrate is decomposed by heat without coloration; the oxide is less acted on by acids than the other oxides of the same group; and sundry other peculiar reactions serve to distinguish the new element from thorium, the only element known to possess so high an atomic weight. Chemistry of the Grape.-In order to test the action of certain special fertilizers on the quantity and quality of grapes, Professor C. A. Goessmann instituted a series of field experiments with the Concord grape and the wild purple grape (Vitis labrusca, L.), an account of which is published in vol. ii. of the Proceedings of the American Chemical Society." His examination was for the most part confined to the berries and the juice of the grapes. The former were tested for the amount of water they lost at 100° C., and the total dry matter left behind at that temperature. The juice of the grapes, obtained after crushing in a hand-press, was examined for its specific gravity, its percentage of grape sugar, and its free acid. Ash analyses also were made, but a detailed discussion of their results is withheld by the author for the present. The following tables show the results of experiments with grapes not fertilized: growers consider the Delaware and the Clinton as derived from the same wild variety, the Riverside grape (Vitis riparia, Mich.), which appears doubtful, judging from the reaction with basic acetate of lead; for the juice of the Delaware grape gives a cream-colored precipitate, while that of the Clinton produces a bluish-green one, indicating quite different pigments in these varieties. On opening the tap in front of the blast-pipe this superheated steam passes down the small pipe outside the generator, and blows with considerable force into the blast-pipe, carrying with it by induction a stream of air. In this way the requisite oxygen to support combustion and steam for decomposition are driven An Economical Heating Gas.-When steam into the apparatus, from which they issue as is passed over coke or charcoal at a red heat, al details of the working of the machine would a permanent gas To describe fully the severrequire more space than can be afforded here, but the whole subject will be found treated in Journal of the Society of Arts," No. 1325. The chemical reactions which occur in the generator are described as follows by the author of the paper just quoted: dissociation of the elements of the watery vapor takes place, the hydrogen being set free, and the oxygen forming compounds (carbonic oxide and carbonic acid) with the carbon; marsh gas is at the same time produced in small quantity. The proportion of the gases thus generated is, according to Frankland: H, 56.9; CO, 29-3; CO2, 13.8. It is evident that here we have a very important heating gas, if it could be produced economically in considerable quantities. How to do this effectually is the problem which has long engaged the attention of chemists and gas-engineers. This problem would appear to have been solved a few years ago by Joshua Kidd, an English inventor; and the improvements which have since been made on his process justify the belief that a perfectly satisfactory solution has been found of the question of a cheap heating gas for domestic and manufacturing purposes. In Kidd's system perfected the generator consists of a hollow cylindrical body or case of wrought or cast iron. This is terminated below by a cast-iron bottom, having a hole in its center about one half or one third of its own diameter; below this is a second hollow cylinder of the same internal diameter as the hole above it; in this lower cylinder the fire-grate is lodged, the blast-pipe opening into it below the firegrate. When making gas, the bottom of the small cylinder requires to be closed air-tight. This is effected either by means of a flat hinged plate, which is kept tightly pressed against it by a heavily weight extenso in the Carbonic anhydride (CO2) is doubtless first formed by the action of the oxygen of the air upon the carbon of the fuel; this in its passage upward through the heated fuel takes up another equivalent of carbon, becoming reduced to carbonic oxide, CO, thus, CO2+C=2CO, the nitrogen of course passing off unchanged and serving only to dilute the gas. With respect to the steam, this, as explained above, is dewith the formation of hydrogen, carbon monoxide, composed in its passage over the incandescent coal, and carbonic anhydride. The latter in its upward course shares the same fate as the CO, produced by the action of the oxygen of the air, i. e., it takes up another atom of C, and passes into the state of CO. The decomposition of the steam, therefore, adds ma terially to the calorific value of the gas, by enriching it with hydrogen and a further quantity of CO. The composition of the gas produced by this generator, when working at different pressures of water, and with various kinds of fuel, has been determined by analysis. The result is as follows: DESCRIPTION OF FUEL. ed lever, or else by a short cap with a beveled edge Peat charcoal.............. Anthracite... 15 lbs. CH1 = = 10.0 4-9 4.5 5S.0 Anthracite... 60 lbs. and steam coal...... low inverted truncated cone projecting into the gen- Equal parts of anthracite If, now, a fire be lighted in the interior of this machine, and water driven through the coil, that water will be made to boil; steam will be produced which will accumulate in the upper part of the coil, and, if not immediately allowed to escape, will become superheated. 1-4 26.4 H 18.5 CH1 = = 8.9 N = 54.8 100.0 As regards the quantity of mixed gases produced from a given quantity of fuel, this has been ascertained experimentally with the following results: DESCRIPTION OF FUEL. 1. Anthracite.. 2NH3) with excess of ammonium chloride, the Water-pressure Cubic ft. of gas metal would be entirely thrown down as a in lbs. per sq.in. per Ib. of fuel. 2. Equal parts of anthracite and steam coal.. 3. Equal parts of anthracite and steam coal.. 25 4. Equal parts of anthracite and steam coal.. 80 40 5. Anthracite 88.84 94.5 (over) 100-0 It will be seen, therefore, that there is a steady increase in the quantity of gas produced per pound of fuel consumed, as the water-pressure rises from 15 lbs. to 40 lbs. Beyond this point there does not appear to be much advantage gained by still further increasing the pressure. The gas produced is essentially a nonluminous gas. When taken direct from the producer, it burns with a reddish-blue flame. After having, however, been stored in a gas-holder for a few hours in contact with water, the flame loses this red tinge, and the gas burns with a blue lightless flame very much resembling ordinary gas burned in the Bunsen burner. In neither case is there any smoke, soot, or deposit of any kind by the burning gas, the sole products of combustion being water and carbonic anhydride. When the gas is made in considerable quantity, its cost in London is about a quarter of that of ordinary illuminating gas. The Equivalent of Gallium.-Lecoq de Boisbandran has determined the equivalent of gallium by the calculation of gallo-ammoniacal alam, and by igniting the gallium nitrate produced from a known weight of the metal. The slight losses sustained in these two operations affect the value of the equivalent in an opposite manner. The former process gave as the result 70-032 (hydrogen being 1), and the latter 69-698. The mean value, 69-865, may be taken as the first approximation. Considerations founded on a classification of the elements in accordance with their properties and the value of their atomic weights point to a maximum number, 69-97, and a minimum, 69.66 (mean, 69-82). The author enters into some details on the comparison of the spectra of the metals Al, Ga, In, on the one hand, and K, Rb, Cs, on the other, and deduces hence for the equivalent of gallium the value 69-86. New Compound of Palladium.-In a communication to the Paris Academy of Sciences H. Ste.-Claire Deville and H. Debray recite that, on heating a solution of palladium chloride (PdCl) with strong nitric acid in presence of sal-ammoniac, the palladium is converted into an ammonia chloride (PdCl,+NH.Cl), which precipitates in small regular octahedrons of a fine red color, sparingly soluble in water, and, like the corresponding compounds of iridium and platinum, almost insoluble in a concentrated solution of sal-ammoniac. The authors expected that in heating with aqua regia certain mother-liquors containing ammoniacal palladium chloride (dipalladamine chloride, PdOl, double chloride. The result, however, was otherwise; for, instead of the expected compound, they obtained a reddish-black substance, Pd,Cl,2NH,, being a combination of ammonia with a palladium chloride hitherto unknown. New Process for the Regeneration of Spent Gas-Lime.-A new process for regenerating the foul or spent lime of gas-manufacture has been introduced into many gas-works in England. It is known as Bishop's process, and is described in an address delivered by Mr. John Mayer in the Chemical Section of the Glasgow Philosophical Society. In this system the kiln consists of a series of four calcining chambers arranged vertically over each other, and, together with the furnace underneath them, occupying the space of one of the ovens of the retort-bench. They are about 9 feet long and 2 feet wide. All the chambers are constructed of fire-clay tiles and blocks of similar form. The gases from the furnace pass backward to its farther end, and rising enter, by means of two ports at the corners, the lowermost calcining chamber, thence over the top of and in close contact with the spent lime, to the fore end of the same; and thence up through two ports as before, traversing the second chamber in the same way; then the third chamber; and, lastly, the topmost or drying chamber, from which they enter the main flue, the opening into which is regulated by a suitable damper. The spent lime is first charged into the drying chamber by means of a shovel, and it remains in that chamber during the regeneration of the contents of the chambers underneath; and after the latter have been discharged into an iron wagon or barrow, the contents of the upper chamber are discharged into the lower chambers through a port near the front of each, the opening of which is covered with a suitable tile, as the chambers are successively filled, commencing at the lowermost; and the gases from the furnace, while passing over and in close contact with the spent lime, disengage the carbonic acid and other impurities. Air is admitted through ventilating flue-boxes, placed on either side of the furnace near to the ground, whence it is conveyed to and directed against the fuel in the furnace near to the center of the furnacebars, where it issues from a number of holes about 1 inch in diameter, pierced through fireclay blocks, which form part of the sides of the furnace. These air-holes pass through the blocks with a dip of about 1 inch toward the furnace-bars. In practice it is found that one man can attend to two sets of chambers, such as those just described, and regenerate upward of 50 cwt. of spent lime per shift of twelve hours, with a consumption of about 8 cwt. of fuel, which is usually the coke of ordinary cannel coal. Hydrogen Peroxide.—The amount of hydro gen peroxide in the air and in atmospheric deposits is the subject of a recent exhaustive report by Schone, of Moscow. His investigations extended from July 1, 1874, to June 30, 1875, and were conducted with wonderful patience and care. He examined 215 specimens of rain and hail, and snow and sleet were tested on 172 occasions. Seven samples of rain and 86 of snow appeared to contain no peroxide. tion of hydrogen peroxide containing 3 or 4 per cent. was mixed with a 10 per cent. sodium-hydrate solution, in equivalent proportions. A rise of 4° or 5o C. took place with a very slight evolution of gas. On concentrating the solution in a vacuum, efflorescent crystals separated on the edges at first, and then large tabular crystals formed in the solution. If, instead of evaporating the solution, once and a half or twice its volume of absolute alcohol be added, and it be allowed to stand in a cool place for twenty-four hours, spear-shaped crystals, often several "centimetres long, appear in the solution. On analysis they give numbers agreeing with the formula Na2O, later by Fairly in the same manner, and with those (HO). They are identical with those obtained obtained by Vernon Harcourt by solution of sodium dioxide in water. When rapidly heated in a glass tube, the crystals melt, froth, evolve oxygen and leave sodium hydrate. In closed vessels, the same decomposition takes place more slowly, requiring three months for completion. Absolute alcohol preserves it pretty well, if carbon dioxide be excluded. On examining the efflorescence above mentioned, it was found to be a mixture of the substance already described and of another substance having the formula Na2H4O6, or Na2O2(H2O2)2, a compound of 80dium peroxide with hydrogen peroxide. To prepare it, a mixture of one molecule of sodium hydrate and about three and a half molecules of hydrogen peroxide solution are mixed and evaporated in vacuo. The crystals are colorless and very minute, are at first transparent, very soluble in water, dissolve in this and in dilute acids without evolution of gas, and effloresce in dry air. In vacuo over sulphuric acid they lose four molecules of water, leav The deposits brought by the equatorial currents always contained more peroxide than those falling at times when the polar currents opposed them; and when the polar stream of air predominates, the relatively smallest yield of peroxide is obtained. The amount attained a minimum in December and January, very slowly increased until April, was very much higher during May and June on to July, when it culminated. During the next three months it fell rapidly, and in November again very slowly approached the minimum. The hail of summer contained a comparatively large amount of the peroxide, although it is less abundant in hail than in rain; and the winter rain yields more of this compound than snow falling at the same period. The total amount of hydrogen peroxide which reached the earth's surface during the year is computed by the author to have amounted to 109.4 milligrammes to the square metre-that is to say, in 599.9 litres of water, or 1049 kilog. to the hectare. The peroxide present in the air in a state of vapor was collected and determined by producing artificial dew with the aid of freezing mixtures; and it was found that the risc and fall in the amount so obtained corresponding NaHO. A similar peroxide hydrate was ob ed and went hand in hand with the numbers obtained by testing the atmospheric deposits. The diurnal variation was studied, and it was ascertained that the maximum amount was present at about 4 the minimum being attained between midnight and o'clock in the afternoon, after which it diminished, 4 A. M. The air of a large hall, which had been unoccupied for four weeks and the windows of which were closed but were not air-tight, was observed to contain an average of 0.17 c. c. peroxide in 1,000 cubic metres. In dew artificially deposited in a badly ventilated room there was no peroxide; its presence, however, became manifest as soon as the windows were thrown open. Dew and hoar frost deposited during the last hours of the night appeared to be pure water; in dew collected during the evening hours peroxide was met with, the amount being 0.05 gramme to the litre. The peroxide is present in fog, and is apparently more abundant in spring than in autumn. The amount of peroxide present in any atmospheric deposit varies with the altitude at which that deposit has been formed; the greater the altitude at which the condensation takes place, the greater is the quantity of peroxide which it will contain. This is doubtless due to the decomposition which that substance must undergo when exposed to organic vapors rising from the earth's surface. In the air itself there is but little peroxide, the maximum quantity observed being 14 c. c. in 1,000 cubic metres of air. The author points out the scientific advantages which would attend systematic observation in this field at meteorological stations. The same euthor has investigated the relations of hydrogen peroxide to the alkalies, with particular reference to the decomposing action of the latter on the former. Of this research we append an excellent summary, published in the "American Journal of Science" : His first efforts were directed to the production of peroxide hydrates of the alkalies analogous to those of the alkaline earths. For this purpose a solu tained with potassium, though mixing the solutions and evaporating gave only a yellow amorphous mixture of potassium tetroxide and potassium hydrate, K2O4+ (KOH+H2O). But if excess of hydrogen results, which is very hygroscopic and has the forperoxide be used, and the evaporation be conducted at a low temperature, 10° C., a white opaque mass mula K2H40, or K202(H2O2)2. These facts the author uses to explain the "catalytic" action, as follows: The decomposition of hydrogen peroxide in alkaline solutions is due, first, to the tendency of the alkalies to form compounds of the composition R2H4O or R2O2 (H2O2)2; second, to the tendency of the alkali metal within this compound to oxidize itself to a higher oxide, the tetroxide; and, third, to the reduction of the tetroxide to dioxide by the water present. New Discovery in Thermo-Chemistry.-A discovery of importance in thermo-chemistry has been communicated to the Paris Academy of Sciences, by M. Maumené. Concentrated sulphuric acid, he writes, which has been left for some months standing, undergoes a singular change of condition. On mixing a liquid such as olive oil with, say, one tenth of its weight of fresh concentrated acid, a certain constant rise of temperature is observed; but if acid three months old is used, the rise of temperature so obtained has a value of about 8° Cent. less. The same results occur even if the acid has been hermetically sealed in glass tubes. With water and other liquids analogous results are found. It is evident that some of the most important data of the thermal effects of chemical action may require revising in the light of this discovery. timony.-A new mode of separating arsenic New Method of separating Arsenic and Anfrom other metals is offered by Messrs. De |