by its discoverer, Mr. Deacon, for the direct manufacture of bleaching-powder from the gases issuing directly from the salt-cake furnace. Air is admitted, together with hydrochloric acid gas, and the mixture is passed over red-hot bricks impregnated with copper salt. The oxide of copper acts as by contact and remains unaltered, whilst the chlorine, watery vapour, and excess of air pass at once into the lime-chamber. There are many practical difficulties in working this process on the large scale, some of which have still to be overcome; but I believe we shall hear from Mr. Deacon that, notwithstanding these drawbacks, he has accomplished his end of making good bleaching-powder by this process.

On the Alloys of Copper, Tin, Zinc, Lead, and other Metals with Manganese. By J. FENWICK ALLEN, F.C.S.

In the year 1826 a spoon, made by Messrs. Zernecke, of Berlin, was analzyed, and the alloy was found to be composed of copper 57.1 per cent., manganese 19-7 per cent., zinc 23.2 per cent. This analysis is included in a chapter on Kupfermangan, by Mr. Johann Tenner, in his Handbuch der Metall-Legirungen,' published at Quedlinburg. Berthier produced a large number of alloys of manganese with various metals, and has recorded their principal properties.

Whilst, therefore, the alloys of copper, zinc, and other metals with manganese have been more or less known to the metallurgist for more than forty years, whilst their valuable physical properties have been fully described, whilst, moreover, manganese in its ores almost approaches iron in its abundance and in its value, and yet for years has been suffered to escape as a waste product from almost every large alkali-works, we find the metallurgist has not succeeded in reducing it to serve widely except when yoked with iron.

To produce metallic manganese was not from the first attempted; and it is with extreme difficulty that even small quantities of this metal can be prepared.

From the first it was discovered that in using any of the ores of manganese, the iron and the silicon completely destroyed the value of the product. Having ob tained a comparatively pure oxide of manganese, recovered from the "still liquors," and having mixed this with oxide of copper (not metallic copper), together with wood charcoal, all finely ground and intimately mixed, the charge was put into a plumbago crucible, then heated in an air-furnace at an intense heat from three to four hours. When the pot was taken out, it was found that, still suspended in the charcoal, and not run down to the bottom, there were innumerable fine shots of a bright white metal; these, being separated by washing and placed again in the crucible and heated, fused into a pill or button covered with a layer of green vitreous slag. The process was continued until some small ingots were produced; and on these experiments were made as to their malleability and ductility.

The alloy was found to be very hard and very brittle when hot; but when cold, although still hard, it rolled with ease, and was highly elastic. The proportions of the alloy were about:-copper 75 per cent., manganese 25 per cent. When the simple alloy had been produced in sufficient quantities, compound alloys with zinc were tried in various proportions; and these, again, rolled with complete success. Certain mixtures of copper, zinc, and manganese possess the advantage over both German silver and yellow metal, that, whereas the one will only roll cold and the other hot, the manganese alloy rolls from hot to cold.

As a simple alloy, in which the proportions of manganese range from 5 to 30 per cent., it is both malleable and ductile, with a tenacity considerably greater than that of copper.

With zinc a compound alloy, resembling in some of its qualities German silver, is obtained.

The alloy of copper and manganese combines with tin, lead, and other metals; and from these castings are made, and applied as bearings for machinery, and other similar purposes.

It was not the nature of the metal itself that prevented it being widely used; it was its cost. The waste of manganese is very considerable, over 10 per cent. remaining unreduced, and forming a silicate; the wear and tear of the plumbago

pots and the furnace incurred a large expense; and in proportion to the quantity of metal produced, the fuel consumed and the labour expended were great.

The waste of manganese in alloys rich in that metal will, it is feared, always be considerable; but the value of the raw material would permit some such loss, could the other points be obtained; and these, it is believed, have now been achieved.

The metal has been produced by heating a mixture of carbonate of manganese with oxide of copper and charcoal in a tolerably large reverberatory furnace, and not in a small and costly pot. The fuel used has been principally the common slack or small coal of the district, and not coke. The labour has been proportionately reduced; and a series of alloys are produced that ere long promise to play no unimportant part in the arts and manufactures.

It is the excellent furnace-arrangements of Mr. Siemens that have assisted in overcoming the difficulties at first encountered, by affording the intense heat needed, with a non-oxidizing flame, in a quiet atmosphere.

The following specimens were exhibited :—

1st. Manganese and copper, in various proportions from 35 to 5 per cent. of manganese, as ingot, sheet, and wire.

2nd. Copper, zinc, and manganese; also in different proportions, and in a variety of applications.

3rd. Copper, zinc, manganese, and tin; as ingots and as bearings.

4th. Copper, manganese, and tin, in several different proportions; as bars.
5th. Copper, manganese, and lead.

On the Chemical Composition of the Bones of General Paralytics.
By J. CAMPBELL BROWN, D.Sc.

Total inorganic consti- |

tuents

Organic constituents.

Ratio of lime to phosphoric acid....

24.24

22.85 19.09 23.52 23:31
28.54 25.25 29.57
•43 37 41
1.29 2.09 1.55

16.89

25.95

28.98

36

22:20 32.98 34.43 1.05 1.37 1.67

1.10

1.71 3.37

2.90

49-46 53-11 46-8 55-05 53.75 41.85 61.96 64.95 50.54 47-02 53.5 44.84 47.15 58.16 38.02 33.97

100.00 100.13 100-3 99-89 100.90 100-01 99-98 98-92

I. shows the average proportions of organic and earthy matter in several samples, which were remarkable only for being less perfectly developed than the ribs of healthy adults; some of these had been fractured and perfectly united; others were entire.

II. These ribs were not fractured, nor did they contain much fat; but they were thinner than usual.

III. consisted of one rib only; it was slender, and rough and jagged on the edges, but had not been fractured.

IV. consisted of six ribs, which had all been fractured, and had completely united, and showed a slight callosity; some of them had been again fractured more

*This specimen also contained fat which had not been removed before analysis.

recently, and had only imperfectly united; they contained an unusual amount of fat. Portions of the ribs were removed and freed from fat before they were submitted to analysis, and the remaining portions were handed to the Curator of the Museum of the School of Medicine.

V. For comparison with these, I give the composition of the femur and tibia of a nine months' foetus in column V., and of the bones from a case of osteomalacia in column VI.

VII. is calculated from the analysis of a healthy adult tibia by Valentin. VIII. is calculated from analyses of ribs of a healthy man, aged 25, by Von Bibra. It will be observed that the ratio of organic constituents to earthy matter is much greater, while the ratio of lime to phosphoric acid is distinctly less, in the ribs of paralytics than in those of healthy adults. There are the same differences between the composition of healthy ribs and those of paralytics as between the composition of the adult large bones and those of the foetus; and, generally, the composition in cases of paralysis approaches that observed in cases of osteomalacia. Whether the defects in the ribs of paralytics are due to arrested development or to degeneration of the fully developed bone, it will require further experiments upon carefully selected cases to prove; but from the evidence already obtained the author was led to conjecture that both causes will be found to operate.

The result of the analysis is suggestive rather than conclusive as to the condition of the bones in patients the subjects of general paralysis; and it would be unsafe to generalize from a few examples. The analysis, however, is a first instalment towards determining, by scientific inquiry, whether the statements that have been made, as to the peculiar liability to fracture of the bones in certain forms of insanity, holds good as a general rule.

On a Spectroscope in which the Prisms are automatically adjusted for the Minimum Angle of Deviation for the particular Ray under examination. By JOHN BROWNING, F.R.A.S.

In spectroscopes of ordinary construction, when several prisms are employed, a great deficiency of light will be noticed towards the more refrangible end of the spectrum.

This arises from the fact that the prisms are adjusted to the minimum angle of deviation for the most luminous rays, which are near the other end of the spectrum. The Diagram shows the method in which the change in the adjustment of the prisms to the minimum angle of deviation for each particular ray is made automatically. In this diagram P, P, &c. represent prisms. All these prisms, with the exception of the first, are unattached to the plate on which they standthe triangular stand, on which the prisms are hinged together at the angles corresponding to those at the bases of the prisms; to each of these bases is attached a bar B, perpendicular to the base of the prism. As all these bars are slotted, and run on a common centre, the prisms are brought into a circle. This central pivot is attached to a dovetail piece, two or three inches in length, placed on the underside of the main plate of the spectroscope, which is slotted to allow it to pass through. On moving the central pivot the whole of the prisms are moved, each to a different amount, in proportion to its distance in the train from the first or fixed prism, on which the light from the slit falls after passing through the collimator C. Thus, supposing the first prism of the train from C, represented in the diagram, to be stationary, and the second prism to have been moved through 10 by this arrangement, then the third prism will have moved through 2o, the fourth through 30, the fifth through 40, and the sixth through 5°. As these bars are at right angles to the bases of the prisms, and all of them pass through a common centre, it is evident that the bases of the prisms are at all times tangents to a common circle.

*

Now for the contrivance by which this arrangement is made automatic. A lever L is attached to the corner of the triangular plate of the last prism; this lever, by its further end, is attached to the support which carries the telescope through which the spectrum is observed. Both the telescope and lever are driven by the * It really has a slight movement round one angle.

micrometer-screw M. The action of the lever is so adjusted that, when the telescope is moved through any angle, it causes the last prism to turn through double that angle. The rays which issue from the centre of the last prism are thus made

to fall perpendicularly upon the centre of the object-glass of the telescope T; and thus the ray of light travels parallel to the bases of the several prisms, and ultimately along the optical axis of the telescope itself, and thereby the whole field of the object-glass is filled with light.

Thus the apparatus is so arranged that, on turning the micrometer-screw so as to make a line in the spectrum coincide with the cross wires in the eyepiece of the telescope, the lever L, attached to the telescope and prisms, sets the whole of the prisms in motion, and adjusts them to the minimum angle of deviation for that portion of the spectrum.

On the Examination of Sea Water on board H.M.S. 'Porcupine,' in July 1870, for dissolving Gases and varying proportions of Chlorine. By W. LANT CARPENTER.

Contributions to Mineralogical Chemistry. By A. H. CHURCH, M.A., F.C.S.

Experiments on the Preservation of Stone. By A. H. CHURCH, M.A., F.C.S.

On the Purification of Public Thoroughfares by the application of Deliquescent Chlorides. By W. J. COOPER.

The author had first called attention to the subject in 1868; at that time a very successful experiment had been tried in Baker Street, Portman Square. In Liverpool, in 1869, Bold Street, Church Street, and Lord Street were watered with salts during the month of July. The report of the result was very favourable, and the experiments have been continued this year. In many towns experiments have been tried during the past season, with various results, according to tle composi

tion of the roadways. It is difficult to prove the economy resulting from the use of the chlorides over a limited area; but over large areas it is very evident. The importance, in a sanitary point of view, of the use of chlorides has been clearly established. The chloride of calcium decomposes the carbonate of ammonia contained in the horse-droppings, the results being carbonate of lime and chloride of ammonium, which two results, combining with the chloride of sodium and the carbonate of lime contained in the roadway, cause the concreting effect so important in the prevention of dust and the preservation of the roads.

A new Chlorine Process without Manganese (with illustrations).
By HENRY DEACON.

A heated mixture of hydrochloric acid gas and oxygen or air are passed over heated salts of copper, lead, or manganese, or pieces of burnt clay, or similar porous bodies previously soaked in solutions of the salts. Under these circumstances the chlorine of the hydrochloric acid is set free; and the action is so complete that, by proportioning the surfaces of the salts and current of gases, the whole of the chlorine can be liberated or all the oxygen or air absorbed. At 750° F. the reaction is most active with copper salts; lead salts require a higher temperature, and manganese salts still higher; and as the temperatures increase, it is believed chlorine reacts on the vapour of water produced to re-form hydrochloric acid. With copper salts no such re-formation occurs. If the temperature be too high, chloride of copper always sublimes, whatever salt of copper be first employed.

The author predicted this reaction, so far as the chloride of copper and of manganese are concerned, from the belief that chemical forces may be united and resolved as mechanical forces are, and as, he believes, is evidenced in the ordinary manufactures of sulphuric acid and of sulphuric ether by the continuous processes. The positive proof or disproof of this theory appears only to be possible by considering the time occupied. If a result follows from the formation and subsequent decomposition of a compound, the total time will be the time of the two processes added together; but if it be a direct result of the union of the forces, it will be the time only of either process alone. This proof being at present unavailable, the author relies on the test of the other proof of a correct theory, viz. its power of foretelling unknown events, and claims in this instance to have shown the great probability of the truth of his theory, admitting that it is not yet strictly proved.

Note on Thermal Equivalents.-1. Fermentation. 2. Oxides of Chlorine. By JAMES DEWAR, F.R.S.E.

On Cyanogen. By THOMAS FAIRLEY, F.C.S., Science Master at the Leeds Grammar School.

I. Preparation of Cyanogen.-The author has found the most convenient method for the preparation of cyanogen to be the action of one part of pure potassium cyanide, dissolved in as little water as possible, on two parts of powdered copper sulphate, mixed with scarcely more water than sufficient to moisten and cover it. The operation may be performed in an ordinary bottle or flask; and the cyanide solution should be added a little at a time, as the action is very rapid. Much water prevents the action. Besides its convenience, this method gives at least two 15ths of the weight of the cyanide as cyanogen. Careful experiments, made with mercuric cyanide, show that it is very difficult to obtain more than one 15th of its weight as cyanogen, i. e. only one third of the cyanogen it contains.

II. Hydrogenation of Cyanogen.-In a former paper the author showed that when cyanogen and hydrogen are passed over platinum black at 140° C., they combine. He has repeated and extended these experiments, and finds that the substance obtained by passing the gases into dilute hydrochloric acid is the chloride of an organic base containing C, H, N, Cl in the exact proportions of the chloride of ethylene diammonium. The chloride is soluble in absolute alcohol, and, heated with alkalies, gives off a liquid base. The chlorplatinate is very soluble in water, and soluble to