rules of the new association may be founded. The following were nominated by ballot to serve on this committee :Prof. Abel, Mr. Carteighe, Prof. Frankland, Mr. W. N. Hartley, Mr. Neison, Dr. Voelcker, Dr. C. R. A. Wright. The Royal Society.-Yesterday being St. Andrew's Day, the Anniversary Meeting of the Royal Society was held. The following Officers were elected for the ensuing year: President-Joseph Dalton Hooker, C.B., M.D., D.C.L., LL.D. Treasurer-William Spottiswoode, M.A., LL.D. Secretaries-Prof. George Gabriel Stokes, M.A., D.C.L., LL.D.; Prof. Thomas Henry Huxley, LL.D. Foreign Secretary-Prof. Alexander William Williamson, Ph.D. Other Members of the Council-Major-General John T. Boileau; Warren De la Rue, D.C.L.; Prof. P. Martin Duncan, M.B., P.G.S.; Prof. William H. Flower, F.R.C.S.; Prof. Michael Foster, M.D.; Edward Frankland, D.C.L.; Francis Galton, M.A.; William Augustus Guy, M.B.; John Russel Hind, F.R.A.S.; The Rev. Robert Main, M.A.; William Pole, C.E., Mus. Doc.; The Rev. Bartholomew Price, M.A.; Rear-Admiral G. H. Richards, C.B.; Henry Clifton Sorby, Pres. Mic. Soc.; Prof. Henry J. Stephen Smith, M.A.; Prof. Balfour Stewart, M.A. MEETINGS FOR THE WEEK. MIDDLESBROUGH; Newfall Tar Works, Carlton; and Ammonia Works, Stockton-on-Tees. Manufacturer of Benzole, Toluole, Xylol, Solvent and Burning Naphthas, Carbolic Acid and Disinfecting Powder, Refined Anthracene, Naphthaline, Black Varnish, Refined Tar, Crude Liquid Ammonia, Galvanising Salts, Coal-Tar, Pitch Creosote, Grease, &c., &c. S. A. S. is always a buyer of Coal-Tar Naphthas, Crude Anthracene and all Tar Products. All communications to be addressed to the offices at Middlesbrough. MANUFACTURED BY WILLIAM BAILEY & SON, ROBERT DAGLISH & CO., BOILER MAKERS, ENGINEERS, AND MILL-WRIGHTS, BRASS AND IRONFOUnders, ST. HELEN'S FOUNDRY, LANCASHIRE. Makers of every description of Chemical, Colliery, Copper Ore, Gold Mining and Glass Machinery, including Crown, German Sheet, and Plate Glass Plant, as supplied to some of the largest Firms in England, Ireland, Scotland, and Wales. Makers of the latest Improved Revolving Black Ash Furnace with Siemens's Patent Gas Arrangement, and as used in the Manufacture of Soda. Improved Valveless Air Engines, and Pumps or Acid Forcing, Air Agitators, Compressors for Collieries, and Weldon's Patent Chlorine Process. Caustic, Chlorate, Decomposing, and Oxalic Pans. Pyrites Burners for Irish, Norwegian, and Spanish Ores. JOHN GRAHAM, CHEMICAL ENGINEER, FARNWORTH, NEAR MANCHESTER. Plans, Contracts, Estimates, Specifications, and Valuations; Competent Workmen sent to all parts of the Graham's Improved Burner Pipe, a sure preventative against the Destruction of Lead in Towers and Chamber Ends, and a Perfect Remedy against any Escape of Gas. TO USERS OF ALL KINDS OF ACIDS OR CORROSIVE LIQUIDS. 11 kinds of Acids Supplied at Remarkably Low Rates. Distance no object; at Sender's risk; Carriage Paid. Apply to SUTCLIFFE BROS., Climax Works, Birkenhead. GEO. G. BLACKWELL, MINERAL BROKER AND MERCHANT, CHAPEL STREET, LIVERPOOL, Has a Speciality in MANGANESE ORE. LUMP, of every percentage for Chemical and every requirement. ARSENIC, White Refined powdered, Lump, Grey, and Ruby. FLUOR-SPAR, the finest produced, for Opal, Acid, and Flux. WILLIAM FOX & SONS, Wholesale and Retail Chemists, SUPPLY BARYTES, CHLORATE POTASH, PHOSPHORUS, STRONTIA AND OTHER CHEMICALS, Pure and Commercial, at Market Prices. Pri e List post free on application. 109 & 111, BETHNAL GREEN ROAD, LONDON, E. CARBONATE OF BARYTES, Selected Lump and Ground. TOWNSON & MERCER BAUXITE, Magnesite, Emery Stone, Chrome Ore, English, Italian, and FRENCH CHALK, China Clay, Flints, Cryolite, and all other MINERALS, ORES, &c. Supplies by Contract and in large and small quantities, at the lowest rices, direct from Mines or Works, or from stock held at the Manganese Oxide and Mineral Works, Garston. NEWTON, KEATES, & CO., Sutton Oak Manure Works, ST. JELENS, LANCASHIRE MANUFACTURERS OF Concentrated Superphosphate of Lime, LIEBIG per cent Soluble (guaranteed), Commercial Phosphoric Acid, PHOSPHATE OF SODA, AND Phosphatic Gypsum. FLETCHER'S INJECTOR FURNACE, SMALL SIZE, WILL MELT HALF A POUND OF CAST-IRON IN EIGHT MINUTES, USING LESS THAN SEVEN CUBIC FEET OF ORDINARY GAS AND STARTING WITH THE FURNACE COLD. The loss of heat by radiation is nil, the outer casing remaining absolutely cold. Its power is limited only by the capability of resistance to fusion of the refractory casing. Half a pound of steel can be melted and poured in less than twenty minutes. It is absolutely secure against loss by boiling over or cracking of a crucible in the melting of valuable metals, &c., and turns out sounder and tougher ingots of gold, silver, &c., than any known furnace. Hot-Blast and other Blowpipes, Special Gas Furnaces with and without blast for Spectroscope Analysis, Cupelling, Enamels, Roasting Ores, &c. Burners and Blowpipes for all temperatures from that of a drying closet to the fusion of platinum. Foot-blowers giving any required pressure of air with perfect steadiness up to 4 lbs. on the square inch. Special designs to order without extra charge. Detailed list with engravings on application to THOS. FLETCHER, F.C.S., MUSEUM STREET, WARRINGTON, Manufacturer of Platinum Alloys, Oxychloride of Zinc, &c., for Dentists. (See Loan Collection of Scientific Apparatus, South Kensington, Section 8. COMPANY'S EXTRACT OF MEAT Finest Meat-flavouring Stock for Soups, Made-Dishes and Sauces. Caution.-Genuine ONLY with facsimile of Baron Liebig's signature across Labei. PATENTS.-Mr. Vaughan, F.C.S., British Foreign, and Colonial PATENT AGENT. Special attention given to Inventions relating to Chemistry, Mining, and Metallurgy. Guide to Inventors" Free by Post.-Offices, 67, Chancery Lane, London, W.C., and 8, Houndgate, Darlington. BERNERS COLLEGE of CHEMISTRY, in conjunction with the SCIENTIFIC DEPARTMENT of the ROYAL POLYTECHNIC INSTITUTION. Instruction and preparation in CHEMISTRY and the EXPERIMENTAL SCIENCES under the direction of Professor E. V. GARDNER, F.A.S., M.S.A. The Class Rooms are open from 11 to 5 a.m. and from 7 to 10 p.m. daily. Especial facilities for persons preparing for Government and other examinations. Private Pupils will find every convenience. Analyses, Assays, and Practical Investigations connected with Patents, &c., conducted. Prospectuses and full particulars on application to Prof. Gardner at Berner's College, 44, Berners-street, W., or at the Royal Polytechnic Institution. MORRIS TANNENBAUM, 37, FITZROY STREET, offers Jewellers, Mineralogists, Lapidaries, and specially Collectors of Rare Cut Gems (which he possesses in all existing kinds), large Collections of Fine Hyacinths in all Colours, Clear Spanish Topazes, Blue and Yellow Amethysts, Jargon, Olivine, Fossils, Fine Collections of Shells, Thousands of Indian Pebbles. Polished Agates, &c., Starstones and Catseyes, Garnets, Cape Rubies, Fine Slabs of Lapis Lazuli, Fine Emeralds in the Matrix, Fine Crystallised Rubies and Brazilian Topazes, and Thousands of Rare Opals. Specimens and for Cuttings. Orders effected to all parts of the world. INDIA-RUBBER SPECIALLY PREPARED FOR CHEMICAL PURPOSES. Boots, Gloves, Gauntlets, Aprons, Pure Tube and Hose, all Warranted Best Quality. J. G. INGRAM & SON, Manufacturers of Mechanical, Surgical, Chemical, and all other Vulcanised India-Rubber Goods. The London India-Rubber Works, Hackney Wick, E., AND AT HOXTON AND RAINHAM, ESSEX. Electrical and Philosophical Instrument Maker to the F. W. HART, Manufacturer and Dealer in H. M. CAPNER, Trade only. SQUARE, LONDON, E.C. Apparatus and Chemicals for Scientific Pursuits. Labora tory Fitter and Furnisher. Photographic Apparatus and Materials. 8, KINGSLAND GREEN WEST SIDE), LONDON. zero, where the spot of light normally rests. The vertical NEWS. figures represent the seconds during which the experiment lasted. The zigzag line represents the oscillations of the spot of light, and shows the movement of the pith surface under the influence of a uniform source of radiation. The time was recorded by a chronograph. Starting from zero the spot of light is seen to have travelled to 97° in 115 seconds; at the end of 11 more seconds, or 22.5 seconds altogether, it had come back to 50°; at the end of 34 seconds the light had advanced again to 109°, and so on. The movements are tolerably uniform as to time, taking about 115 seconds for the half oscillation, but the amplitude of vibration is continually diminishing ON REPULSION RESULTING FROM RADIATION.-PART II.* By WILLIAM CROOKES, F.R.S., &c. 106. IT was found that when a source of light and heat is suddenly allowed to shine on the pith surface and not removed, a deflection rapidly takes place, attaining its maximum in about 11 seconds; the spot of light now returns a few degrees, and then proceeds in the first direction to a greater extent than at first. So it goes on, by alternate steps, advancing a little each oscillation, 107. If, however, the light is only allowed to shine on the pith surface for 115 seconds (or for as long as the spot of light takes to perform its first half oscillation), and if it is then instantly cut off, the spot of light almost invariably returns to zero and stops there, instead of swinging to the opposite side and only returning to rest after ten or a dozen oscillations, as is the case when the beam is set vibrating by mechanical means. This behaviour FIG. 9. Degrees on scale, representing repulsion. until, if the light be feeble, the index takes up a nearly fixed position; if, however, the light be strong, the beam is driven against the side of the tube. In illustration of this I select the following series of observations from a large number recorded in my note-book. The horizontal figures represent the degrees on the scale, starting from A Paper communicated to the Royal Society, March 20, 1875. From the Philosophical Transactions of the Royal Society of London, v1 clxv., pt. 2. points to the return movement taking place under the influence of a force which remains active after the original radiation is cut off, and which is only gradually dissipated. This force is most probably from the heat which the pith has absorbed raising its temperature; and the steady return to zero seems to be due to the movement being controlled by the radiation of heat by the pith. 108. A series of observations taken with another apparatus, with the object of ascertaining the times o 3 20 96 15 2 3725 175 0.62 or consisting of polished metal) of the body on which radiation falls materially influence the movements. 109. The accompanying table gives the results of numerous experiments as to the effect of screens, tried with an exceedingly delicate apparatus, constructed as above desribed, the window, c' (fig. 7), being of quartz. The candle used was the kind employed in gas photometry, and defined by Act of Parliament as a "sperm candle of 6 to the pound, burning at the rate of 120 grs. per hour." The distances were taken from the front surface of the pith when the luminous index stood at zero. They were in the proportion of 1 to 2 (140 to 280 millims.) to enable me to see if the action would follow the law of inverse squares and be four times as great at the half distance. No such proportion can, however, be seen in the results, the radiant source possibly being too close to allow the rays to fall as if from a point. The figures given are the means of a great many fairly concordant observations. Where a dash rule is put I have tried no experiment. The cipher o° shows that experiments were actually tried but with no result. The sensitiveness of my apparatus to heat-rays appears to be greater than that of any ordinary thermopile and galvanometer. Thus I can detect no current in the thermopile when obscure rays from copper at 100° C. fall on it through glass; and Melloni gives a similar result. (To be continued). 7:00 Mean..7'47 Mean..14'77 The average time of the first half oscillation is therefore 747 seconds, and of the second half 7.3 seconds. This small difference is not unlikely to be due to errors of observation. After a long series of experiments the zero gradually creeps up, showing that one side of the apparatus is becoming warmed. The conducting power for heat and condition of the surface (whether coated with lampblack * By referring to paragraphs 106 and 107 it will be seen that I have put the time of the first half oscillation as 115 seconds. This was with another apparatus, having a glass thread of different torsion. ESTIMATION OF POTASSIUM AS ACID TARTRATE.*, By P. CASAMAJOR. (Concluded from p. 233.) If we should be in entire ignorance of the quantity of potassium in a compound to analyse, we should take a large quantity of tartaric acid, not more, however, than three times as much as the quantity of material weighed for analysis, as the monosulphide, which is the compound having the greatest percentage of potassium, has 71 per cent, which, multiplied by 4, gives 2.84. The next in order, potassic hydrate, has nearly, but not quite, 70 per cent. To return to the 10 c.c. of decinormal solution, we may note that they contain 47 centigrms. of potassa, corres * Read before the American Chemical Society, September 7, 1876. NEWS ponding to 39 centigrms. of potassium. We may then weigh approximately 2 grms. of tartaric acid, which is a little less than six times the quantity of potassium to be precipitated. This acid is dissolved, and added to our Io c.c. of decinormal solution. The liquid should now be stirred sufficiently to make a thorough mixture of the solutions of potassa and tartaric acid. The crystals begin to deposit almost immediately, and the deposition increases for about five or six minutes, when it stops, and the liquid clears up. Alcohol should now be added to increase the precipitate. This addition, however, requires a few words of explanation. As the result of numerous estimations of potassium in compounds of various kinds, I have found it advantageous to add, at first, only a small quantity of alcohol, a volume about one-tenth of the liquid in the beaker-glass. After this addition the liquid should be stirred sufficiently to effect a thorough mixture, and then be allowed to rest five or six minutes, when the liquid above the precipitate becomes clear once more. Finally, the rest of the alcohol should be added, a quantity sufficient to make the whole liquid in the beaker-glass contain at least 60 per cent of alcohol in volume. The liquid in the beaker should be stirred up once more, and after becoming clear it should be thrown on a filter. To ensure in an easy manner a quantity of alcohol equal to 60 per cent of the total volume of liquid, I mark on the side of a beaker-glass a line corresponding to 50 c.c., which is easily done with a file, previously moistened with petroleum or spirits of turpentine to prevent the abrasion from cracking the glass. 50 c.c. are quite sufficient when we take 1 grm. of material for analysis. The volume of the beaker-glass should be at least 200 c.c. This volume of 50 c.c. is for the solution in water before adding alcohol. In the case we have on hand, we have dropped 10 c.c. of decinormal solution of potassa in a glass, and added a solution of tartaric acid. We may now add water up to the mark indicating 50 c.c. On the other hand, we have strong alcohol-say, of 93 per cent-which is the strongest common alcohol found in the market, and which is sold under the name of 95 per cent alcohol. I have no intention of giving rules for mixtures of alcohol and water, which are familiar to most chemis.s. In this case I will call your attention to this-that if you add 100 c.c. of 931 per cent alcohol to the 50 c.c. of liquid in the beaker-glass, the result will be 150 c.c., and if we divide 93 by 150 the result, 623, will be the strength of alcohol required. After adding about 10 c.c. of strong alcohol to the 50 c.c. of solution in our beaker-glass, we finally add the rest of the 100 c.c. After the deposition of crystals has stopped, the contents of the beaker are thrown on a filter. The liquid that filters through gives a distinct red colour to litmus paper. The precipitate on the filter should now be washed with alcohol of 60 per cent until the filtered liquid ceases to show a red colour with litmus paper. The precipitate after this is ready to be washed down into a beaker-glass to be tested with potassa, after the liquid in the glass has been sufficiently heated and coloured with litmus. The glass containing cream of tartar in water is placed under a burette, and, if the operation has been carefully conducted, it will take exactly 10 c.c. of the decinormal potassa solution to turn the liquid in the beakerglass from red to blue. The condition of a solution containing only potassa and water is one that very rarely, if ever, presents itself in chemical analysis, and we have in the next place to ascertain the influence of bodies which are usually found in combination, or in a state of mixture, with potassium. If we drop 10 c.c. of a decinormal solution of potassa in a glass, and add a few drops of solution of litmus, we will be able to find the quantity of sulphuric acid, added drop by drop, which will neutralise the 10 c.c of potassa. *When soda is present in the solution it is expedient not to delay too much in throwing the precipitate on a filter to avoid errors in the result. I propose in a future communication to examine this question. After doing this, if we add as before 2 grms. of tartaric acid dissolved in water, a very slight precipitate will be obtained, even after standing for hours, and however much the liquid may be stirred, or whatever quantity of alcohol we may add, the precipitate does not increase perceptibly. If, instead of stopping at neutrality, a sufficient excess of sulphuric acid is added, tartaric acid will not show the least turbidity after continued agitation and addition of large quantities of alcohol. Hydrochloric acid in the same circumstances behaves exactly in the same manner, as is also the case with nitric and phosphoric acids. From the behaviour of potassic bromide and iodide, when in presence of an excess of tartaric acid, we must conclude that hydrobromic and hydroiodic acids belong to the same category. With all these acids, a quantity sufficient for neutralisation of the potassa gives a slight precipitate, while an excess prevents precipitation. In the first case, the precipitate produced can only take place by liberating a quantity of the acid in combination, and after a sufficient quantity of free acid has been formed further deposition is prevented. The acids experimented on were powerful mineral acids, whose affinities for potassium are so great that, although the acid tartrate is more insoluble than any of their potassic compounds, they only yield a small portion of potassium to tartaric acid. If, therefore, a weaker acid than the tartaric was chosen to combine with potassium, it would not prevent the production of an abundant deposit of acid tartrate. Acetic acid naturally suggested itself, and, on being tried, was found incapable of preventing this precipitation. Here, then, was our way out of the difficulty. Before describing the manner in which this property of acetic acid was utilised, we must, for the better understanding of the subject, state that salts of sodium in a solution containing 60 per cent of alcohol do not prevent the precipitation of cream of tartar. The sulphate, the nitrate, the chloride, iodide, and bromide, the tartrate, and acetate seem equally powerless to prevent the formation of the precipitate. This is an important point, as by means of soda or its carbonate we may separate the bases that accompany potassium and ammonia, whose acid tartrate is very insoluble, and may in presence of soda be driven off by heat. The property that acetic acid posseses, of allowing the complete deposition of cream of tartar to take place, suggusted at first the following process:-Given a compound containing potassium, phosphoric acid, if present, would be separated as ammonio-magnesic, as tricalcic, or in any other convenient phosphate. The volatile acids could be driven off by excess of sulphuric acid and heat until fumes of sulphuric acid began to appear. Sulphuric acid could afterwards be precipitated with acetate of barium, thus leaving acetic acid as the only acid in the solution, in combination with all the bases. This process is simple in theory, but long, and altogether detestable in practice. An analysis was already begun on this plan, when another, much more simple and convenient, suggested itself, which gave on trial the most satisfactory results. This process consists in adding to the compound to be analysed, if it contains a strong mineral acid, a certain quantity of acetate of sodium and, afterwards, tartaric acid. The effect of adding acetate of sodium is that if a strong mineral acid is in excess it forms a sodium salt by acting on the acetate, and liberates a corresponding quantity of acetic acid. When tartaric acid is afterwards added, and a quantity of acid tartrate is precipitated, the strong mineral acid set free reacts on the acetate, and acetic acid is again liberated. This action goes on until all the potassium has been precipitated as acid tartrate, and all the strong mineral acids originally combined with potassium have been combined with sodium, and a corresponding quantity of acetic acid has been set free. The quantity of acetate of sodium that I usually add is equal to the quantity of tartaric acid. The theoretical |