NEWS

sulphites of sodium and calcium (the latter formed by decomposition). The remaining calcium sulphite together with the filter was brought into a beaker and titred with solution of iodine. 45.85 c.c. solution of iodine were used, corresponding to about 0.0032 grm. sulphurous acid. At the first titreing the sulphurous acid was present as hyposulphurous acid, therefore required only half the iodine solution =22'9 c.c.; the hyposulphurous acid consequently required 7.64 22'9 c.c. = 53'5 c.c. = o'0096 hyposulphurous acid. 25 c.c. lye contain therefore :45.85 0.0032 0.1467 sulphurous acid, and 53'5X0'0096=0'5136 hyposulphurous acid. 01467 sulphurous acid correspond to o 275 calcium sulphite with o'0733 sulphur, and 0.0917 calcium o'5136 hyposulphurous acid give o'8453 sodium hyposulphite with 0.3424 sulphur, and o'2461 sodium.

25 c.c. lye gave 0057 barium sulphate, corresponding to 0033 calcium sulphate, with o'008 sulphur and o'or calcium.

Determination of the Total Lime.-25 c.c. lye were mixed with an excess of ammonia, and the lime precipitated by ammonium oxalate. After well known manipulations 1247 grms. calcium carbonate were obtained, corresponding to 0'499 grms. of calcium.

Determination of the Total Soda.-25 c.c. lye were boiled with hydrochloric acid until the precipitated sul phur had conglomerated, filtered, the lime precipitated by ammonia and ammonium oxalate, and the sodium in the filtrate weighed as chloride. Result-1032 grms. sodium chloride, corresponding to 0'405 grm. sodium.

Determination of the Total Sulphur in 25 c.c. Lye.-5 c.c. lye were mixed with little water, and then powdered copper chloride was added; after the addition of fuming nitric acid heat was applied. The undissolved sulphur weighed o'175 grm.; the sulphur in the form of barium sulphate o 0756 grm.-together 0.2506 grm. sulphur. 25 c.c. lye contain, therefore, 1253 grm. sulphur.

Determination of the Sulphydrate.--The sulphuretted hydrogen liberated from the sulphydrate in the lye by solution of iodine was estimated with a standard solution of potassa according to Mond's method. 25 c.c. lye required 43 75 c.c. potassa solution corresponding to about 000321 sulphuretted hydrogen. For the liberated molecule of sulphuretted hydrogen this amounted to o'14 sulphuretted hydrogen, and for the total sulphur of the sulphydrates, therefore, 0.263 sulphur. If from the 0'405 sodium the sodium contained in the hyposulphite = o'1461 is deducted, there remains o'1589 sodium as sulphydrate; this weighs 03869 grm., with 01174 sulphuretted hydrogen. This quantity deducted from o'14 grm., which were found, leaves o0226 grm. sulphuretted hydrogen for calcinm sulphydrate; these give o'0704 grm. calcium sulphydrate with o'0266 grm. calcium.

Determination of the Polysulphurets.-If, from the total quantity of sulphur, = 1.253 grms., there is deducted the sulphur of the sulphurous hyposulphurous and sulphuric acids, and of the sulphydrates, i.e., o'6867 grm., there remain 0.5663 grm. S; if the calcium of the calcium sulphite, sulphate, and sulphydrate is deducted from the total quantity of sulphur found, there remain o 3707 grm. Ca, which are combined with the above 0.5663 sulphur to polysulphurets.

I have made the remark, that, bisulphide of carbon will take up sulphur from the lye. This observation, as well as that, that during the oxidation of the soda waste in the air sulphur is separated, proves, that besides the tetrasulphuret the lye must contain pentasulphuret and free sulphur. The two values for sodium and sulphur correspond to 1 mol. calcium, and 1'9 mol. sulphur, which might lead to the assumption of the compound CaS2 in the lye. The presence of large quantities of tetrasulphuret in the lye, as well as the quantity of sulphur which is precipitated by carbonic acid, entirely contradict this view, not taking into account that Schöne has proved the non-existence of these compounds in solution. Again, it is not possible

| to assume the whole of the calcium as 4CaO.CaS4+18aq., because in this case too large a quantity, of the total sulphur, ought to be present as free dissolved sulphur. If we try to combine calcium and sulphur to tetra- and penta-sulphuret, the proportion representing the formula CaS5+4ÑâO.CaS+18aq., agrees best. According to this view 5 parts of calcium require 6 parts of sulphur; therefore o 3707 calcium, 0'445 sulphur. The remainder of the sulphur o'5663-0'445 01213 grm. is then dissolved as such. Therefore, 25 c.c. lye contain o 309 CaS, with 00618 calcium, and o 246 sulphur, 1106 (4CaO.CaS4)+18aq.

with 0.309 Ca and o 198 S.

By passing carbonic acid through the lye, only these two last compounds are decomposed with the separation of sulphur; the former yields, the latter of its sulphur together, therefore 0.246. 08+0198.075=0'3453 S, to which must be added o1213 free sulphur, o'4666 grm. altogether. The direct experiment gave 0'468 and 0'472, mean 0'470 grm. S, which quantity almost completely corresponds with the one calculated.

The investigation, furthermore, proves that carbonic acid must precipitate all the lime as carbonate, for the sodium sulphydrate, converted into carbonate, is present in sufficient quantity to completely precipitate the calcium sulphite. After decomposition by carbonic acid, boiling, and filtering, the lye contained no more lime.

If we review the results of the analyses, we find that 25 c.c. of the examined lye contained :—

Behaviour of the Lye towards Sulphurous Acid.Schaffner decomposes the lye by hydrochloric acid and passes the sulphurous acid, which appears after the sulphuretted hydrogen, into fresh lye, thereby converting the sulphurets into hyposulphites with the separation of sulphur; the hyposulphites are again decomposed by hydrochloric acid, sulphur being precipitated and sulphurous acid evolved. The sulphur resulting from this process contains considerable quantities of calcium sulphate, whose formation, according to Schaffner, is due to the sulphuric acid of the crude hydrochloric acid, whilst Mond, as has been mentioned, explains it by the formation of trithionic acid, which is formed during the decomposition, and later at an elevated temperature, is split into sulphuric and sulphurous acids and sulphur. The latter theory alone is correct, for the conditions of the formation of trithionic acid are existing under the given relations. Of course the calcium sulphate formed in this manner is increased by that from the sulphuric acid of the crude muriatic acid.

If pure washed sulphurous acid is passed through the sulphur lye, it is completely decomposed, considerable quantities of sulphuretted hydrogen being evolved and a yellow precipitate being formed, the temperature rising at the same time. In this case the action of the sulphurous acid was continued until lead paper was no longer coloured, the liquid had a neutral reaction, and did not, therefore, contain an excess of sulphurous acid. At this stage it contained calcium and sodium hyposulphite, and was completely free from sulphites. The filtered yellow precipitate was pure sulphur, free from calcium hydrate or sulphite, burning on platinum foil without leaving a residue. Consequently the decomposition does not take place in such a manner that difficultly soluble calcium sulphite is precipitated; but the sulphurous acid acts exactly like the carbonic or hydrochloric acid, it decomposes each single compound, sulphur and sulphuretted hydrogen being separated and combining with the bases,

it is instantly converted into hyposulphurous acid by the nascent sulphuretted hydrogen. This process, practised by Schaffner long since, is especially adapted to the manufacture of sodium hyposulphite; the lye, which has been treated with sulphurous acid until neutral, is decomposed either with sal-soda or soda ash; calcium sulphate or carbonate is precipitated, and there remains a concentrated solution of hyposulphite of soda, which after evaporation gives the salt almost pure. For lyes, which like the one examined can be completely purified from lime by carbonic acid, this process may be employed; but part of the sodium is then converted into carbonate. In this case, the sulphur being mixed with large quantities of carbonate of lime, might, perhaps, not be easily recovered.

If the lye, which has been neutralised with sulphurous acid and filtered, is again subjected to the action of sulphurous acid, no sulphur is precipitated, thus affording proof that the sodium hyposulphite is not decomposed; but if the liquid is heated on the water-bath, very soon a precipitate of sulphate of lime and sulphur is formed. In order to further elucidate this behaviour, a solution of pure calcium hyposulphite was heated, whereby according to the statements made hitherto, the salt ought to be split into calcium sulphite and sulphur. I have convinced myself, that even after protracted boiling this reaction is only a subordinate one, that, on the contrary, the salt is chiefly decomposed according to the formula CaS2O3+H2O=CaSO4+SH2, calcium sulphate being formed and sulphuretted hydrogen evolved slowly but steadily.

If sulphurous acid is added to the solution of hyposulphite of lime and the whole heated on the water-bath, the liquid is coloured yellow, and after concentration suddenly a heavy precipitate of sulphate of lime appears, whose quantity cannot be compared with that formed without the addition of sulphurous acid. I was tempted to the belief that this decomposition takes place in this manner, because the sulphurous acid commences the process; this, however, is not the case, for if little sulphurous acid is added to the hyposulphite of lime, very little sulphur is precipitated, and the liquid contains sulphuric acid, but even after heating it on the water-bath for some

length of time, no sulphate of lime is precipitated; only soon after adding an excess of sulphurous acid a heavy precipitate of sulphate of lime is formed. In the presence of sulphurous acid the decomposition of the hyposulphite of lime takes place in a different manner from that without it; the conditions for the formation of trithionic acid being given, first calcium trithionate is formed, which, on heating, is decomposed into sulphate of lime, sulphurous acid, and sulphur.

If the calcium hyposulphite is mixed with a little hydrochloric acid and heated, a precipitate of sulphur and sulphate of lime is formed; also in this case the sulphurous acid from the hyposulphurous acid has formed trithionic acid, which then was decomposed with the formation of sulphuric acid. If the quantity of hydrochloric acid necessary for the complete decomposition is added at once, no calcium sulphate is formed. The sodium salt behaves like the calcium salt; according to the quantity of hydrochloric acid it gives, when heated, sulphuric acid or not; in the latter case with an excess of hydrochloric acid the hyposulphurous acid being decomposed into sulphur and sulphurous acid.

The behaviour of the hyposulphurous acid in the sulphur lyes towards sulphurous acid is the same as that of the pure solutions of hyposulphurous acid, no matter whether the sulphurous acid be directly added or formed in the lye: the latter is always the case when the lye is decomposed by muriatic acid.

If the sulphur lye is heated to 60° C. and carefully mixed with hydrochloric acid, sulphur is separated and sulphuretted hydrogen evolved, but the sulphur re-dissolves, as I have already remarked. After a further addition of hydrochloric acid sulphur is precipitated, the lye is discoloured, and towards the last gives off sulphurous acid.

This proves, that also here first the sulphurets and sulphhydrates are decomposed, and only later the sulphites and hyposulphites with the evolution of sulphurous acid. If the volume of the decomposed lye, which contains a certain quantity of free sulphurous acid, is just sufficient to convert into hyposulphites all the sulphurets and sulphydrates of the fresh lye which has been added, the process has been conducted faultlessly, i.e., the smallest quantity of sulphate of lime is formed. If, on the contrary, the process of decomposing the lye is executed in such a way as to leave free sulphurous acid after the formation of those compounds, trithionate is instantly formed, which soon afterwards gives, by decomposition, sulphate, in our case calcium sulphate.

In Schaffner's process, where after decomposing the lyes by muriatic acid the free sulphurous acid is passed into fresh lye, a large quantity of sulphate of lime is. formed, which seems to indicate that the quantity of sulphurous acid is too large. The reason, I think, is that the oxidised waste is very rich in hyposulphites, and that, therefore, by the decomposition of the lyes with muriatic acid too much sulphurous acid is liberated.

I am not able to precisely state how to operate on a large scale, for, as has been proved by others, the composition of the lyes is subject to great fluctuations; but the trithionates play an important part, as stated by Mond, and it is advisable to conduct the decomposition of the lyes by muriatic acid and the action of the sulphurous acid, or that of the decomposed lye on fresh lye, in such a manner as to exclude the formation of trithionates.-American Chemist.

PYROLOGY, OR FIRE ANALYSIS.* By Captain W. A. ROSS, R.A. (Continued from p. 70).

Fish-tail Flames.

25. If a pyrochromatic substance be held on the loop produced by blowing strongly, the current is broken upon of a platinum-wire in a rapid hydrocarbonous current, it so as to form a kind of fish-tail flame at its rear, i. e., the side turned from the base of the pyrocone, in the blue matter of which its front is enveloped as usual. The inner sides of this fish-tail flame will, after a short time, be observed to be deeply and continuously tinged with the colour which is the chief characteristic of the substance burned. A far stronger pyrochromatic reaction is thus obtained than by holding the substance in the position usually adopted, of what is called "the point of the outer the superposed blast is too violent, and carries away the flame," or, in fact, in an oxyhydrogen pyrocone; for here

colour as soon as formed.

The Oxyhydrogen Pyrocone. (O. P.) 26. In which the object is held as at c, Fig. 1. It is flame;" but that the two first of these appellations are commonly called "the oxidating, oxidising, or outer incorrect is shown by the fact that when some metallic oxides, as those of gold, silver, or mercury, dissolved in a flux more delicately sensible to oxidation and reduction than borax or microcosmic salt, viz., phosphoric acid, are held in this position, the bead, so far from being further oxidised, immediately precipitates its contents, and becomes dim or opaque in consequence.

mingling of the two currents-of air and ignited hydro27. This pyrocone appears to be caused by the intercarbonous matter, its broadest part being at a, where they may be supposed to cross each other, giving it a slightly oblate appearance.

Communicated by the Author. From the Proceedings of the Royal Society. The substance should occasionally be dipped in distilled water.

NEWS

30. These are invariably supported on platinum-wire in the admirable and perfect manner invented by Gahn, and, as soon as a pyrocone is applied, assume the form of a spheroidal bead, which revolves or spins round upon its centre with a rapidity proportional to the fluidity of the matter of which it is composed. The 'glasses' "beads thus formed, with the oxides dissolved in them, may be quantitatively determined, as to their weight and size, by means to be presently described.

ог

31. Berzelius informs us that "Cronstedt used but three reagents-basic carbonate of soda, borate of soda, and the double salt of phosphate of soda and ammonia. These reagents are still in use; and among the great number of those which have been tried since that time, not one has been found to replace either of these. It is singular enough that, in the very beginning of the art, the very best reagents should have been hit upon." ("Berzelius on the Blowpipe," p. 32).

32. One of the objects of this paper is to attempt to show that the two last fluxes mentioned in the above paragraph are not only not "the very best reagents," but that they have, by the complicated and obscure results obtained necessarily from their compound nature, seriously retarded the progress of pyrognostic examination. For instance, speaking of the third flux mentioned, the metaphosphate of soda, produced from what is commonly called microcosmic salt, Berzelius says (p. 39),-"Its efficiency as a reagent depends principally on its free phosphoric acid; and it is preferred to this because the phosphoric acid cannot be kept without deliquescing, while at the same time it is much dearer, and is also easily absorbed by the charcoal. The salt of phosphorus shows, therefore, the action of an acid upon the substance to be

tested."

Phosphoric Acid (Symbol P).

33. Now, if glacial phosphoric acid be heated until it melts into a substance of viscid or gum-like appearance, and be thus poured hot into a wide-mouthed stoppered bottle (which should also be hot when receiving it), it can not only be kept without deliquescing, but, when solidified by cooling in the bottle, may be carried about in the pocket without fear, kept for years in the most rainy climate, and allowed to remain, even for hours, with the stopper of the bottle off. It has also the great advantage of being nowa-days far more easily procured pure enough for the purpose from most respectable chemists, even in out-ofthe-way stations, as in India, in consequence of its use in therapeutics, than microcosmic salt can be. It is used by simply dipping the red-hot platinum-wire loop and the glass, of whatever description, formed upon it into the bottle, when a fresh supply of phosphoric acid adheres to the hot bead, without the supply in the bottle being at all adulterated.

34. That the metaphosphate of soda does not, when heated, exert upon substances added to it the reactions of an acid, unless the basic soda be displaced by another

base for which the acid possesses a greater attraction, must be evident to an ordinary chemist; and there would appear to be few substances for which phosphoric acid has a greater attraction than it has for soda; in fact, the most valuable pyrognostic reactions prima facie of the acid upon substances have been lost to operators precisely because the salt it forms with soda fails to give us those acid reactions, as follows:-The acid effervesces violently with all carbonates, and with some of the metallic oxides, by many mineralogists and geologists of carrying about -the salt does nothing of the sort; and the necessity felt in their pockets a phial of the unpleasant and dangerous hydrochloric or nitric acid is thus at once obviated.

46

35. The acid used to dissolve cobalt oxide in any considerable proportion is blue-hot, but assumes on cooling a magnificent red-violet colour,* to which the modern word magenta" is partly applicable. When soda or potash is applied to this glass in sufficient proportion (about 17 per cent) to form the metaphosphate of those bases, the glass remains blue, and a standard of alkali for purposes of calculation is thus evidently obtained. But as cobalt oxide produces with this flux many shades of colour, according to the quantity in which it is added, from a pale and scarcely perceptible pink to the deep crimson-violet above mentioned, and as these degrees of red are exactly azurised by a corresponding strength or quantity of the alkali added, it is plain that a kind of chromatic scale or table of colours might thus be made of great use in the quantitative measurement of alkalies on the one hand, or of cobalt oxide on the other, instead of the unvarying "blue" which we find opposite oxide of cobalt in all blowpipe tables.

36. Instead, therefore, of superfluously multiplying illustrations of the difference between the reactions of the pure acid used as a flux and of the assumed free acid" in microcosmic salt, it will be better to give here in slight detail some of the more important of the former with

various oxides.

Gold.

37. Is dissolved and oxidised by this flux in an O. P. (as at a, Fig. 1), when added in minute portions of the is more powerful as a solvent than any one of the mineral leaf, a fact which suggests that P under these conditions acids. As stated in paragraph 26, the position (a, Fig. 1) bead of a dirty or muddy appearance, which the applicawill precipitate the dissolved gold oxide, rendering the tion of a P. P. (as at 3, fig. 1) will soon remove, the bead fractive. If this brilliant auriferous glass be now treated then appearing not merely diaphanous, but highly rewith a good H. P., the white metallic-looking filin referred to in par. 15 is formed, with a slight but distinct shade of yellow-like pinchbeck, which is apparently due to the gold in solution; and this bead may thus be made alternately diaphanous and metallic-looking as often as is desired.

38. If the auriferous transparent bead be carefully kept for some time about an inch from the point of the whole pyrocone, or 2 inches from the blue, as at 2, Fig. 1, a beautiful shade of bluish-rose-colour flushes over it just as it is becoming cold; and the production of this tint, which cannot be confounded by the dullest observer with the red-violet of cobalt, or the amethyst tinge of titanic acid or manganese, is an excellent test of the skill of the operator, as well as of the delicacy of the pyroconical reactions in this flux, for a hair's breadth too far towards 3, Fig. 1, will cause the glass to be diaphanous and colourless on cooling; while a corresponding error in the other direction towards I will, as has been mentioned, produce a muddy appearance.

39. Gold-leaf is more rapidly dissolved, and the above reactions more easily produced in a glass of phosphate of lime, which appears to be, under pyrological conditions, a * Discovered by the writer on July 12th, 1869.

Lithia and its salts will not apparently azurise this cobaltine glass, but afford with it a very pretty purple-violet colour. ↑ The addition of fresh phosphoric acid at this stage brings out this beautiful reaction still more decidedly.

more powerful solvent of metallic oxides than any other known flux. It will be afterwards described; but it has the disadvantage in analysis, referred to in par. 32, of being a salt.

40. The ruby colour bestowed by gold upon glass and fluxes would thus appear, by the experiment above detailed, to be due to an exact amount of oxidation. The oxides of tin and and antimony, added with it to colourglass under the name of "purple of Cassius," &c., seem not to have anything to do with the production of the colour.†

Silver.

cially arsenic acid, by which a glass is thus produced quite equalling in appearance the finest topaz.

46. If this glass be now returned to an O. P., as at a, Fig. 1, the oxide is immediately precipitated with a dim, and often an opaque grey or grey-black, appearance; and although mercuric oxide (for instance) is usually presumed to be of so volatile a nature that its reactions are not given in blowpipe tables, this mercurial oxide is so difficult to volatilise that the strongest O. P. will not clear the P bead from it, but only burn both slowly away. Sulphur.

47. If sulphur be added to a P bead, as described in par. 45, and then treated with a P. P., the curious result of chromatic reactions exactly similar to those of copper, of plumbic oxide heightens this effect; and the resulting blue bead is quite indistinguishable from a cupreous one placed alongside. Nitrogen.

42. There are two ways of effecting this. First, for an ore supposed to contain only a small percentage of silver. If the slightly argentiferous glass be retained in the position 3, Fig. 1, the yellow precipitate soon disappears, and the glass becomes clear, highly refractive, and brilliant. On changing its position in the pyrocone to that of a, Fig. 1, at present called the "oxidising flame," the yellow precipitate immediately and copiously reappears; but there is no visible mark or signification by which the operator can thus judge of the quantity of silver oxide added. When, however, this amounts to 5 per cent of the whole glass, and the latter, rendered diaphanous by the first position, is suddenly and momentarily brought into the second one indicated above, or, better, to just the tip of the blue, from whence, however, it must be instantaneously removed, a very remarkable and very beautiful appearance results. It is that of an almost perfect imitation of a pearl, produced apparently by the reduction of the oxide near the surface to the metallic state, while a vitreous glaze or gloss is still retained upon the surface.

43. This, then, may be called the first standard of silver for ores containing that oxide up to 5 per cent, though of course it may be used for richer ones; but the following method is more rapid for a rich ore, provided there are no chromatic oxides present to interfere with the clearness of the glass.

44. Second, for rich argentiferous ores. If we continue adding oxide of silver to a weighed P glass, and dissolving it carefully as at 3, Fig. 1, we shall find the glass remains diaphanous until 20 per cent of the oxide has been added, when the yellow creamy precipitate again begins to appear, causing, for rich ores, 20 to be the standard of silver. Of course, in calculating results from these "standards," the ratio deducible from them must be of the inverse kind; that is, for instance, if we find an argentiferous ore requires to be added to the extent of 40 per cent in order to produce the yellow precipitate in a P. P., as at 3, Fig. 1, or just double the quantity of the pure oxide of silver to effect the same result, we take the proportion of Ag as just half of purity, or 50 per cent.

Mercury and the Volatilisable Metals in P.

45. If these oxides are taken upon the hot glass, and the mass inserted into a good H. P., as in Fig. 4, they are neither volatilised nor dissolved. The volatile oxides under such conditions form part of the metallic-looking crust or film, which is invariably formed over the surface, and can thus be added in large quantity with a very trifling loss. If the mass be now treated with a P. P., as at 3, fig. 1, these oxides are rapidly dissolved, all of them bestowing on the P glass a brilliant golden-yellow, espe

No metal, not even gold, has any tendency to alloy the platinumwire in this flux when kept under a P. P. [Phosphofluate of lime gives with gold oxide a bead as blue and brilliant as a sapphire.September 14th, 1872.1

After a time these

48. If a P bead be constantly dipped in the strongest possible solution of ammonia or in concentrated nitric acid, and immersed as often in a H. P., as Fig. 4, numerous black specks will be found on the surface like carbon, but much more difficultly burned away appear to combine with the metallic-looking film which is formed by the H. P., and the substance is then by no with nitrogen will be found to be clear hot, yellow and means easily volatilised. The glass thus impregnated gelatinous on cooling, therein exactly differing from those of the alkalies, the volatilisable oxides, and some of the earths, which are yellow hot and clear cold.

Oxide of Copper in P.

and treat it with a P. P. (2, Fig. 1), we find that it takes 49. If we add pure cupric oxide to a weighed P bead, exactly 5 per cent of the whole bead to produce distinctly the peculiar blue of copper. The glass must be carefully held in the position indicated, as O. P. would leave it green:* 5 per cent, then, may be taken to represent the standard of copper for quantitative measurements, as where there is a chromatic interference of other oxides, described in par. 44; but in such cases as Cu pyrites, something more is necessary.

glass in sulphur to give it the cupreous blue appearance 50. It requires one-third more than the weight of a P referred to in par. 47; that is to say, a 50 mgrs. glass of requires 75 mgrs. of flour sulphur added by degrees for that purpose. the flour sulphur, when it assumes the metallic appearance But it is found that by treatment in H. P. referred to in par. 17, is reduced to one-fifth of its bulk; so that 75 mgrs. of flour sulphur only represent 15 mgrs. of the allotropic sulphur, and 15 therefore is taken as the standard of sulphur. It has also been ascertained that sulphurous P bead, cause it to remain green even after a 16 mgrs. per cent of oxide of copper, when added to this P. P., probably on account of the disposal by the sulphur of the superfluous oxygen; 16, therefore, is taken as the equivalent standard of copper to sulphur. If we now add oxide of lead to the green cupreo-sulphurous P bead thus produced, we shall find that, on the addition of 24 mgrs. per cent, the glass will again appear blue; 24, therefore, is taken as the equivalent standard of PbO to sulphur.

51. Copper pyrites dissolved in a P glass has a dirty green appearance, without any shade of blue in it, after a P. P. As an example, it took 571 mgrs. of PbO to azurise a green Cu pyrites P bead of 100 mgrs.

NEWS

Titanium and Tin in P.

53. A diaphanous P glass having either of these oxides dissolved in it will, after being held a considerable time, as at 3, Fig. 1, show (apparently) crystals, yellow with Ti, and white with Sn, produced in it. This result cannot be effected with the mouth, but only with a table pyrogene.

Alumina and Silica in P.

54. Berzelius proposes (p. 86) to estimate silica pyrognostically in a mineral thus:-"Every substance of an earthy or mineral nature, which melts with soda with effervescence into a transparent glass which remains transparent on cooling, is either silica or a silicate in which the oxygen of the silica is at least double the quantity of that of the base." This ingenious discovery, which is strictly correct in cases where it is applicable, and in such cases therefore most useful, is unfortunately inapplicable to those silicates in which the estimation of the silica is of the most importance. The so-called "alkaline earths," especially lime, will not permit silica, though combined in any proportion, to yield a bead with soda transparent on cooling, and they seem also to prevent or cancel effervescence in the same.

55. After many comparatively futile attempts to separate and estimate alumina and silica in various ways, one of which is referred to in par. 18. which occupied the writer some years, the following plan, which ought from its simplicity to have suggested itself at first, has been followed with apparent success. Nearly every oxide or substance is more soluble pyrologically in P than alumina and silica, while alumina is far more soluble than silica is. The alkaline earths" are rapidly dissolved; and lime especially is not only dissolved, but forms a salt, referred to in par. 39, which will dissolve almost anything but silica.

56. It has been ascertained that alumina will dissolve to the extent of 20 per cent, and silica to that of only 6 per cent, in a P bead; and this result is not materially modified by lime. After those amounts respectively have been added, the undissolved alumina appears as white roundish fragments, like pieces of fat, the silica as a semitransparent mass like melting snow, so that they are thus distinguished without difficulty even in presence of lime or the alkaline earths. Six per cent is therefore taken as the standard of silica in quantitative calculations; but as 20, that of alumina, is inconveniently large, it is better to employ as the flux a P bead half saturated with 10 per cent of pure alumina, and to make

Io the standard of that "earth."

57. AP glass saturated with silicic acid still dissolves a little alumina, but the converse is not the case; it is best, therefore, to test qualitatively for either earth with a P glass saturated with alumina.

(To be continued.)

Another mode of procedure with sulphides is to carefully add the roasted ore (which by a method of roasting to be hereafter described, invariably loses just 17 per cent), atom by atom, to the P bead, in a P.P. (when the CuO blue reaction will first appear), until the FeS begins to interfere with it; then deduct from the large amount of copper thus indicated the sulphur and iron as determined by roasting and protoxide of lead.

+ Such as are sold at Freiberg by " Herr Bergmekanikus Lingke," manufacturer to the Royal University of that place; vide Plattner's "Probirkunst mit dem Löthrohre," vierte Auflage (Leipzig, 1865),

p. 31, note.

Borax dissolves silica pyrologically more completely than any known flux. The writer found that phosphoric and nitric acids, com

bined in about equal proportion, attacked and broke up the Berlin

saucers in which they were boiled.

PROCEEDINGS OF SOCIETIES.

CHEMICAL SOCIETY. Thursday, February 6th, 1873.

Dr. WILLIAMSON, F.R.S., Vice-President, in the Chair. AFTER the minutes of the previous meeting had been read and confirmed and the donations to the Society announced, the names of Messrs. James Walker Montgomery, Alexander Bottle, Richard Joseph Deely, and George Ainsworth, were read for the first time; for the third time, Messrs. Charles Lees, John Abigal Bower, Miles H. Smith, George Frederick Ochacht, Alfred J. Cownley, and Walter E. Koch, who were ballotted for and duly elected.

The first communication was from Dr. H. E. ARMSTRONG, "On the Action of Sodium on Aniline." The author said that he was induced to lay before the society the results of his experiments on this subject some years ago, as Messrs. Merz and Weith had recently stated that sodium had no action on aniline. This was correct for temperature below the boiling point of aniline, but when the two substances are heated in a sealed tube to 200°, the sodium disappears, hydrogen is evolved, and a colophonium-like substance produced, which appears to be a mixture ofC6H5 C6H5

N Na and N Na H

Na

It darkens when exposed to the air, and is decomposed by the action of water, with formation of sodium hydrate and reproduction of aniline. With methyl-aniline the action is only partial even at 250°, and with ethyl-aniline there is no action even at 300°. The simultaneous action of potassium and carbonic anhydride on aniline gives rise to potassium carbonate and diphenyl carbamideN2(C6H5)2H2CO.

The latter substance, however, is not always produced, and even under favourable circumstances the amount is but small.

The CHAIRMAN, after thanking Dr. Armstrong for his interesting communication, announced that a paper "On Anthrapurpurine" would now be read by the author, Mr. W. H. PERKIN. After adverting to a paper in which he had mentioned the existence of another colouring matter, differing from alizarine, which was present in crude artificial alizarine, the author stated that he had endeavoured to extract it by repeated crystallisation of the alizarine from various solvents, but, although its solubility differs considerably from that of alizarine, he had been unsuccessful. The method of preparation ultimately adopted was to dissolve the crude colouring matter in a dilute solution of sodium carbonate, and agitate it with freshly precipitated alumina, which removes the alizarine in the form of a lake, and precipitate the impure anthrapurpurine from the filtered solution by hydrochloric acid. This product was purified by repeatedly boiling it with alcohol, crystallising the residue from glacial acetic acid, boiling it with alcoholic soda and decomposing the difficultly soluble sodium compound with barium chloride. The barium compound was lastly decomposed by sodic carbonate, and the resulting purple solution precipitated by hydrochloric acid. The product obtained, after being crystallised two or three times from glacial acetic acid, was found to have the composition C14H8O5. Anthra purpurine sublimes with partial decomposition when heated, is difficultly soluble in alcohol and in ether, but soluble in hot glacial acetic acid, which deposits it in tufts of minute orange-coloured needles. When heated with acetic anhydride to 150° it dissolves, forming triacetyl-anthrapurpurine, C14H5(C2H3O)3O5=C20H1408, a substance crystallising in pale yellow glistening scales, glacial acetic acid, and is decomposed when heated with which melt at 220°-222°. It is moderately soluble in