72
Chemical Notices from Foreign Sources. {

August 18, 1876. the physiological action of magenta free from arsenic, and Bulletin de la Société d'Encouragement pour l'Industrie finds that, though not a violent poison, it produces some

Nationale, No. 32, August, 1876. morbid phenomena. In a state of chemical purity he

Report of M. J. A. Barral on behalf of the Com. considers that its use would not occasion any great in. mittee of Chemical Arts on the Pneumatic Malting convenience.

Process of M. Galland, Introduced at the Brewery Circumstances of Production of the Two Varieties of Maxiville, near Nancy:—The principle of the invenof Sulphur, the Prismatic and the O&ahedral.-M. tion consists in forcing air always at the same temperature D. Gernez.-An account of the precautions to be taken in and always saturated with moisture through the layer of order to obtain sulphur in the two states mentioned. barley with a speed exactly sufficient to remove the excess

Critical Researches on Certain Methods Em. of carbonic acid. The barley may be spread to the depth ployed for the Determination of Vapour-Densities, of 30 to 50 c.m. The results are stated to be very satisand on the Conclusions to be Deduced.-L. Troost | factory. From a statistical table given it appears that and P. Hautefeuille.-Not adapted for abstraction.

the average consumption of beer in Bavaria reaches the

enormous amount of 219 litres per head, that of England Action of Hydracids upon Selenious Acid.-M. A.

being 118. Ditte.-- The author states that the compound SeO2,2 H Br is capable of taking up more bromine, and forming the

Report of M. Lamy on behalf of the Committee compound 2SeO2,5 H Br. He has also examined the of Chemical Arts on the Manufacture of French behaviour of selenious acid with the hydriodic, hydro- | Yeast and of Corn Spirit of Sprenger and Co., of cyanic, hydro-fuoric, hydro-sulphuric, and hydro-selenic Maisons Alfort (Seine).-Not adapted for abstraction. acid.

Observations on Iodine as a Reagent for Starch. –M. E. Puchot.— The author finds that the sensibility of

Revue Universelle des Mines, iodine as a reagent for starch is affected by certain nitro

May and June, 1876. genous organic matters, such as albumen. If albumen is

This issue contains no chemical matter except a paper poured upon iodide of starch suspended in water the colour

on the “ Pyrites used in the Manufacture of Sulphuric disappears. If albumen is added to a solution of starch Acid in France" taken from the Comptes Rendus, and saturated iodine water produces no colouration.

already noticed. Rhodeine, a New Reaction of Aniline.-M. E. Jacquemin.-The author having mentioned that the hypochlorites of lime and soda cease to indicate the pre

M. Reimann's Farber Zeitung. sence of aniline in solutions containing less than 1 centi

No. 25, 1876. grm. in 500 c.c. of water, shows that if after adding the This issue contains a long leader on the condition o test solution of hypochlorite to these dilute solutions there the dyeing trade in Berlin. According to the figures be further added a few drops of dilute sulphide of ammo- given a dyer loses on the average 53 pfennige (about 4d.) nium (1 part to 30 of water) a splendid rose colouration on every kilo. of woollen yarn that passes through his appears. In this manner i part of aniline may be detected hands. It is now nothing uncommon to dye living in 250,000 of water. He gives the name rhodeine to the animals. Some time ago a lady of the demimonde drove colouring matter thus generated. No other oxidising four greys dyed a splendid magenta in the Bois de agent can be substituted for the hypochlorites, and no Boulogne. White lap-dogs are often seen with light blue, colour is obtained if a sulphite or hyposulphite is used green, and rose tails. (We have often seen ducks dyed instead of a sulphide. Diphenylamin and toluydin simi- magenta.) The manufacture of eosin has been comjarly treated produce no such reaction.

menced by A. Poirrier, of Paris. Adion of Water upon the Glycols.-MM. Nevolé. -Not adapted for abstraction.

No. 26, 1876. Existence in Spain of a Bed of Nickel Ores

This issue contains a notice that the method of proAnalogous to those of New Caledonia.-M. Meis. ducing pittakall, a blue colouring matter obtained more sonier.—The ore in question is found in the province of than thirty years ago from beech-wood tar by ReichenMalaga, and is a silicate of nickel free from cobalt, and, it bach, has been re-discovered by Grätzel, of Hanover. is intimated, from arsenic and antimony. The amount

It has the peculiarity of being coloured blue by alkalies of nickel is about 9 per cent.

and orange by acids. The shades produced with it are as

fast as those yielded by indigo. Microzymas of the Bladder as the Cause of the Ammoniacal Fermentation of Urine.—M. A. Béchamp.

No. 27, 1876. -A controversial paper, with reference to the papers of Pasteur, Joubert, and Berthelot (Comptes Rendus, lxxxi., According to the process of Saroz and Chognard (French

Manufacture of Orchil Extract and Paste.page 5.)

patent) the lichens are macerated for a quarter of an hour

in water, to which a little hydrate of lime has been added, Gazzetta Chimica Italiana.

and are then heated in a closed vessel to 100° to 120° by Anno vi., 1876, Fasc, iv.

the introduction of steam at a tension of several atmo.

spheres. The duration of the heating as well as the temOn Hesperidin.-E. Paterno and G. Briosi.-The perature are modified according to the kind of lichens hesperidin examined by the authors was extracted from made use of. The purpose of this heating is the rapid the fruit of the common orange (Citrus aurantium), but it and complete conversion of the lichen acids into orcin. is found also in Citrus limonum, Citrus medica, &c. From The clear liquid is then separated from the undissolved 4000 ripe oranges they obtained 180 grms. of pure hespe- woody matter by a filter, a hydro-extractor, or a press, ridin. 'Its analysis gave the following results :

and concentrated by evaporation. It is then mixed with с

ammonia, and put in a tightly-fitting vessel of iron or wood, н

into which oxygen is conducted. The formation of orcein Of nitrogen there was not a trace.

is thus more rapid than on the common procedure, in

which the extract is left to the action of the atmosphere. Experimental Researches on Electrostatic In. The oxygen prepared by the process of Tessié du Motay duction.-G. Pisati.-Not suited for abstraction.

enters at the bottom of the vessel by means of a perforated Elasticity of Metals at Different Temperatures.- tube : the portion not absorbed is conducted away by a -G. Pisati.-Not adapted for abstraction.

second pipe passing through the lid, and may be reserved

53.80
5.88

Patents.

73 August 18, 1876. for a second operation. The evaporating ammonia escapes

It is intended that the examinations in these several through the same pipe, and is absorbed in water with a subjects should be, as nearly as may be, on the same view to its being re-utilised. When the oxidation is grade, as to the amount of attainment they require. The complete, and the liquid contains an excess of ammonia, experience of the Examiners in Mathematics justifies it is driven off by exposure to the air or by a gentle heat. them in stating that any candidate who has thoroughly To prepare orchil paste, the above-described extract, after mastered the Mathematics of the first B.Sc. examination, concentration and mixture with ammonia, is thickened and who has such an aptitude for the study as would lead with a quantity of extracted lichens, and treated with him to select Pure Mathematics as one of his subjects at oxygen. The closed vessel is provided with a mechanical the second, would find no difficulty in mastering the agitator. When the oxidation is complete the paste is requirements of its programme, by such an amount of allowed to stand for some days exposed to the air, with study, carried on through an eight months' Academical occasional agitation.

Session, as would leave him free to bestow the same

amount of time and attention on two or even three other No. 28, 1876.

subjects. It is understood the amount of proficiency This issue contains a paper on the depressed state of expected in each of the three subjects chosen will be that the tinctorial trades, and an announcement that Dr. Ferd. which the candidate might attain by the steady devotion Springmühl is undergoing a prosecution for having in

to it of about one-third of the sessional work of a diligent sulted Prince Bismark and the Emperor (" Ego et rex

student. In regard to the Doctor's degree a change has meus '').

been made in favour of candidates who prolong the An establishment has been opened in Belgium for ex

interval between their first and second examinations for tracting the wool from grease by means of alcohol and the degree of Bachelor from one year to two or more; as ether. The yield, according to preliminary experiments, such will be allowed to come up for the degree of Doctor of is understood to be large. Similar attempts with other Science within a year of their attaining the degree of Bacheliquids, e.g., bisulphide of carbon and fusel oil (Richter's lor. We shall refer at greater length to the new regulations process), have failed owing to the escape of the solvents.

in our Student's Number, which will be published on

September 15.
No. 29, 1876.

Analysis of the Weissenburg Water. – The This issue, again, contains complaints on the depressed springs of Weissenburg, in the Bernese Oberland, state of the dyeing trade in Berlin and the unremunerative enjoy a considerable reputation as useful in the treatment scale of prices.

of pulmonary affections. Cavities in the lungs are said to Consumers of vanadium salts are cautioned against become cicatrised by its use. Its chemical composition tasting any mixtures in which such are present, or bringing can scarcely be said to throw much light upon its medithem in contact with any part which has been deprived of cinal efficacy. The two main ingredients, according to the cuticle, as they are intensely poisonous. Pr ate of Dr. Stierlin's minute and evidently careful examination, potash and tannin are proposed as antidotes.

are sulphates of lime and magnesia. Lithium is present as chloride and iodide, the latter only in very minute quantity. There is an organic compound having the

odour of blackberries, and also cæsium and rubidium in MISCELLANEOUS.

traces too small for quantitative determination.

University of London.--Several important changes have been made in the regulations for the degrees of

PATENTS.
Bachelor and Doctor in Science, conferred by the Univer-
sity of London. In the Matriculation examination
German may now be substituted for Greek. In place of

ABRIDGMENTS OF PROVISIONAL AND COMPLETE

SPECIFICATIONS. the superficial acquaintance with both Zoology and Botany, formerly required at the first B.Sc. examination, employed therein. L. Brumleu, Newcastle-on-Tyne. April 20, 1875:

Improvements in the production of white lead and in the apparotus there will be a single examination (written and practical) No. 1437. The essential features of this invention consists in first in General Biology, in which a more thorough knowledge effecting the division of the lead to be converted into white lead, and will be required of the simplest forms and elementary | the nation of eli her acetic acid or of acetate of lead, or of mixtures of

then subjecting the same contained in a suitably arranged chamber to phenomena of Animal and Vegetable Life, such as is now

the same, and also to the action of air and of carbonic acid; the made the basis of the teaching of some of the most dis- chamber or chambers being so constructed that a rocking motion may tinguished professors in each department. Thus the

be given to them in order that the white lead formed upon the surface student who may be intending to devote himself specially therein, and a fresh sui face be thereby exposed.

of the lead may be removed by the action of the solution contained to Physical or Chemical Science, will be brought to Improvements in the treatment and preparation of certain chemical apprehend the general conceptions common to the two compounds for the purpose of rendering their carriage, sale, use, and great Organic Kingdoms, without being required to

appiicution more convenient and economical. T. Hyatt, Gloucester

Gardens, Hyde Park, London, Middlesex. April 21, 1875.-No. 1451. master the specialities of either. And the student who My invention relates to the consolidation of chemical substances, such intends to present himself at the second B.Sc. examina- as sal-soda, alum, and other compounds containing water of crystallisation in either Physiology, Zoology, or Botany, or all com

tion, for the purpose of lessening their bulk, and thus diminishing the bined, will have laid the best foundation for those special preventing the waste which arises when such substances are in powder

cost of packing, handling, and carriage, and also for the purpose of studies in the study of General Biology. The regulations or in crystal form; also to make their employment in domestic use, for the second B.Sc. examination are framed with the and in the arts and manutactures, more precise, convenient, and view of allowing the candidate to bring up any three of rials other than the above, when such materials are joined, mixed,

economical. My invention also relates to the consolidation of matethe following nine subjects :

combined, connected, or united to them in the production of new and 1. Pure Mathematics.

useful manufactures, such as soda and seidliiż powders in medicines, 2. Mixed Mathematics.

and such as fireproof compositions, or compounds in the manufacture

of fireproof safes, and in the protection of buildings or other construc3. Experimental Physics.

tions against fire. 4. Chemistry.

Improvements in the manufacture of manure from certain mineral

74

Patents.

{

CHEMICAL NEWS,
Augnst 18, 1876.

Improvements in the manufacture of artificial fuels. C. Kingsford, , in a soluble hyposulphite, the precipitate obtained being gradually Fulham, Middlesex. April 21, 1875.-No. 1458. This invention raised in temperature in order to deposit the sulphide of mercury. mainly consists in consolidating small coal or slack, or similar sub- Improvements in the production of aniline-black for printing and stances, by addition thereto of a composition made of a solution of other purposes, and in dyeing aniline-black. A. M. Clark, Chancery silicate of soda or potash, to which a small quantity of pitch or other Lane, Middlesex. (A communicaiion from W.J. S. Grawitz, Paris.) suitable substance is added, and to enable the pitch to combine with May 1, 1875.–No. 1620. This invention relates to the production of the solution the silicate is heated with a small quantity of four or aniline-black, first, in the form of a paste or powder for printing pur. suitable paste-making materials to convert it into a paste, and while poses, and for the manufacture of colours, varnishes, and inks of all hot the pitch is added. For consolidating the substances the composi- kinds; and, secondly, the fibres of textile fabrics, by the concurrent tion while hot is submitted to pressure. The coal may be ground, reaction on aniline oil of certain metallic salts, and certain chromates and, if desired, mixed with clay and lime, which react upon the sili- or bichromates. cates, and hasten the solidification of the fuel.

A1 im ved method of and apparatus for filtering and deodorisiug Improvements in the manufacture of manure, and in the apparatus sewage so as to prevent rivers being polluted thereby. T. Pape, Great employed therein, J. H. Johnson, Lincoln's Inn Fields, Middlesex. Alfred Street, Nottingham. May 3, 1875.-No. 1625. The chief (A communication from H. 0. P. Lissagaray, Pantin, France.) features of the invention consist in a machine being placed horizonApril 22, 1875.-No. 1484. This invention relates to the manufacture tally on a shaft driven by steam-power, and when once set in motion of soluble and putrescible manure from new products obtained by the the apparatus is self acting, and never need stop except for repairs. special treatment of nitrogenous substances, such, for example, as Improvements in the manvfacture of chlorine. H. Deacon, Appleton leather, wool, and horn, which in their natural condition are insoluble House, Widnes, Lancaster. May 3, 1875.-NJ. 1632. The essential and imputrescible, and also to apparatus to be employed in operating feature of this invention consists in the employment in what is known upon the before-mentioned substances.

as Deacon's chlorine process of the residue of burnt or calcined Improvenients in the manufacture of glucose or grape-sugar from pyrites or sulphurets of iron, such residues being either impregnated rice or other grain. E. E. Pearse, Oberstein Road, New Wandsworth, with a salt of copper, or the copper contained therein, being rendered Surrey. April 23, 1875.--No. 1489. This invention has reference to soluble and active either by means of water or by means of an aciduLetters Patent, No. 1044, 1873, and relates to the use of a small jet of lated solution. water or other suitable liquid to flow in with the grain as it passes Improvements in the manufacture of sulphuric anhydride. E. Soninto the saccharifier through the feed-trough to prevent any tendency stadt, Highgate Road, Middlesex. May 3, 1875.-No. 1638. This to choking. By these means the operation on broken and refuse grain, ) invention consists, first, in substituting anhydrous sulphate of magneas well as the operation on grain that has previously been reduced to sium for the ordinary ferric sulphate or other like substance nsually small particles or powder, is facilitated.

employed in manufacturing or obtaining sulphuric anhydride. At Improvements in the marufacture of perforated blocks of chloride of about the melting point of cast-iron, the anhydride is completely sodrim or chloride of potassium for use in the manufacture of sulphate driven off, and may be condensed in the usual manner. This invenof soda and sulphate of potash. J. Brock, Widnes, Lancashire. tion consists, secondly, in using ordinary magnesium sulphate for the April 23, 1875.-No. 1502. This invention consists in making per- same purpose. The water of crystallisation is first completely driven forated blocks of the salts named by placing the crystals wet from the off at a temperature below a red heat, then the heat is raised, and the boiling pans in frames filled with taper pegs, and then draining, process is continued as in the first part of the invention. turning them out of the frame, and stoving them.

Improvements in the method of ireating grease for the purification Improvements in the method of and apparatus for purifying carbtt- thercoj, to be used in the manufacture of soap and for other purposes. retted hydrogen gas. H. W. Cook, Thurloe Square, Middlesex. J. Hopkinson, Southfield Square, Bradford, York. May 5, 1875.-- No. April 23, 1875.-- No. 1505. The objects of this invention are to econo- 1667. Of the grease to be purified I make a lime or insoluble soap, mise the chemical ingredients employed for the purification of gas. and dissolve out the impure fat with a suitable solvent: I prefer biTo this end the puritying materials (say lime, for instance) are pre- sulphide of carbon applied under pressure or otherwise. The same is sented to the gas in such a manner that they will act energetically on run into a stiil, and the bisulphide of carbon is distilled off, leaving the the gaseous impurities, and will offer continually fresh absorbing impure fat in ihe still. The fatty acids distilled are decomposed by surfaces.

means of an acid; I prefer hydrochloric, which liberates the fatty Improvements in the manufacture of sugar from sugar-canes, and in acids from the lime base. apparatus to be employed therein, which apparatus is also applicable to Improvements in the manufacture of artificial fuel. J. Deere, other like purposes. B. Hunt, Serle Street, Lincoln's Inn, Middlesex. Brighton, Sussex. May 5, 1875.–No. 1680. The fuel is composed of (A communication from A. F. C. Reynoso, Paris.) April 28, 1875.- coal, lime, clay, gypsum, or copperas, mixed with a gelatincus No. 1558. This improved process is essentially diflerent from all solution. those which are now employed, and consists in the complete extraction Improvements in the purification of gas. J. Whitley, Roundhay, of the juice from the sugar-cane or sorghum. For this purpose,

York. May 6, 1875.-No. 1694. This invention describes a means of instead of rolling the cants or sorghum in a mill, the inventor com- purifying gas by filtering it through layers of cotton-wool or other mences by cutting them in pieces by means of cutters or knives suite tibrous material. ably arranged; these pieces are then reduced into a pulp by means of Improvements in apparatus for utilising inflammable fluids for rasps, millstones, revolving cylinders, or plates, or other mechanism illuminating and heating purposes. H. Browne, Raymond's Buildings, or apparatus adapted to lacerate the cellules in order to obtain by the Gray's Inn, Middlesex, May 7, 1875.-No. 1701. This invention has complete crushing thereof a homogeneous paste. The pulp thus for its objects the improvement of the means of employing intlammable obtained is submitted to the action of the ordinary presses, or hydraulic fuirs, such as petroleum, naphtha, and the like, for illuminating and or other presses, or any other process employei to separate the juice heating purposes, and also the rendering the employment for such therefrom. This apparatus may also be employed for the extraction purposes of such inflammable fluids less dangerous, and consists of an of starch from tapioca and other roots, and for the reduction to pulp arrangement of reservoirs, pipes, and cocks for supplying the fluid to of cocoa-nuts and other fruits, or for the treatment of sorghum or the lamps or other apparatus automatically. maize, either for the extraction of sugar or the preparation of food for Improvements in the treatment of substances containing alumina and animals.

iron jor the purpose of obtaining certain usejul substances therefrom. Improvements in apparatus or appliances employed in the manufac- P. and F. M. Spence, Newton Heath, Manchester. May 7, 1875.ture of sulphates of soda and potassa. J. Hargreaves and T. Robinson, No. 1704. This invention relates to the production of a cake of sulboth of Widnes, Lancaster. April 29, 1875.-10. 1576. This invention phate of alumina and iron from minerals known under the name of relates to our direct-action process for the production of sulphates of bauxite. soda and potassa, and consists-(1) In the employment of an overhead A slew or improved process for oxidising anthracea, and improve. steam or other crane for charging the chambers. (2) In using the ments in the colouring matter produced therefrom. C. Heinzerling and said crane in combination with a weighted or other tool for loosening G. McGowan, Glasgow, Lanark, N.B. May 8, 1875.-No. 1712. The the sulphate in the chambers. (3) In employing a revolving shaft features of novelty which constitute this invention are the ireatment provided with expanding cutters to loosen ihe sulphate. (4) In em- of anthracen with bleaching powder, and dilute or non-dilute hydroploying troughs or endless travelling bands to carry away to the desired place the finished sulphate. (5) In lengthening the filling cyanide of potassium.

chloric or equivalent acid, and treating alizarin with cyanide or sulpho. necks, and filling the intervening spaces with non-conducting material Improvenients in the manufacture of soda. J. Mactear, Glasgow, to form a working fioor and prevent radiation. (6) In forming the Lanark, N.B. May 8, 1875.-No. 1714.. This invention relates to an hydrochloric gas fiues of iron to prevent leakage.

improved combination of processes, whereby in the manufacture of Improvements in dyeing or printing. C. A. Martius, Berlin, Prussia. April 29, 1875.-No. 1584. This invention relates to improvements in

soda a part of the operations hitherto required may be dispensed with, dyeing or printing with aniline and other coal-tar colours without the

whilst soda sulphate is more completely separated from the products

and profitably unlised. use of mordants now necessary when those colours are employed, by Improvements in the manufacture of sugar. A. Manbré, Cleveland the employment of the tatry salts of the bases of the aniline colours, Villas, Penge, Surrey. May 8, 1875.--No. 1724. My invention has or the other basic coal-tar colours dissolved in alcohols or in the for its object improvements in the manufacture of glucose-sugar for hydrocarbons of the benzol and petroleum series, the above-mentioned brewing purposes. I have found that by mixing a portion of canesalts being insoluble in water.

sugar with a portion of glucose-sugar, and by subjecting the mixture Improvements in treating slag from blast-furnaces to produce a new to the action of heat and in a vacuum, I am able to produce a new kind article of munufacture. E. 1. Hughes, Chancery Lane, London. of sugar, which I call a “specialite sugar," for making beer, possessing (A communication from M. E. Bergius, Mannheim, Baden.) April 30, all the properties required for producing bitter, India, and other pale 1875.–No. 1595. This consists in treating slag with a blast of steam ales, common beer, stout, and porter of the finest and purest quality, so as to transform it into a cotton-like state, which is called silicate possessing great fullness and great delicacy of flavour. cotton.

Improvements in the production of compounds containing xyloidine, An improved process for the manufacture of red sulphide of mercury. and in the application of the same. D. Spill, High Street, Homerton, A. M. Clark, Chancery Lane, Middlesex. (A communication from Middlesex. May 11, 1875.-No. 1739. This invention relates to ima W. J. S. Grawitz, Paris.) April 30. 1875.-No. 1604. The invention provements in the production and application of xyloidine, and of those consists in manufacturing red sulphide of mercury by dissolving with compounds which consist essentially of what is known as soluble gun. out the aid of heat, and whilst protected from the action of light, I cotton, specially applicable to the manufacture of fusees, fusee tubes either the binoxides of mercury or the salts of the binoxide of mercury and imitation tortoise-shell or turtle-shell.

quite unworked.

中

CHEMICAL News,
o}

Métachromatism, or Colour Change.
August 25, 1876.

75

in others there is simply an alteration of the intensity o THE CHEMICAL NEW S. the transmitted light. Houstor and Thompson,ll in a Τ

paper wherein no reference is made to prior workers,

clearly enunciate the order of change given above. Vol. XXXIV. No. 874.

Hartleyß has made observations on the action of heat on the absorption spectra and chemical constitution of saline solutions. In the substances he has studied he

regards colour-change as evidence of alteration of hy. METACHROMATISM, OR COLOUR CHANGE. dration. By W. ACKROYD, Mem. Phys. Soc.

I. Metachromes, their Deportment and Classification.

A large series of spectroscopic observations were made Many inorganic bodies change colour, when they are of metachromatic solutions, at low and high temperatures, heated, without suffering any alteration of chemical com- for purposes of comparison. The change in most cases position. These changes embrace a class of phenomena is very small, and may readily be confused with sources quite as important in their way as those of phosphorescence of observational error. Our main object being to arrive and fluorescence, with which, in fact, they are intimately approximately at the cause of the phenomenon, solutions connected. We venture, therefore, to propose for the were discarded, and stable anhydrous bodies experimented phenomenon the name of Metachromatism, from the with in their stead. The advantages accruing from this Greek peta, change, and xpwpa, colour, and it will be con- course are many, and such a course is moreover necessary venient to call colour-changing bodies metachromes. for (1) the elimination of chemical action, and (2) a more

Metachromatism has received a fair share of attention decided change in colour, from the greater range of temfrom scientific men in time past. Their labours, however, perature it is possible to employ. The table below are not even referred to in our text-books of chemistry and contains a list of a few anhydrous metachromes, with physics,-perhaps from the importance of the subject their changes, in addition to many of those given by being under-rated, and its bearings not being clearly seen. Schönbein, Gladstone, and Houston and Thompson. Hence when, at an early stage in its study, we saw that The changes were observed on white porcelain in prenearly all metachromatic changes take place in a definite ference to sheet copper, as used by Messrs. Houston and order, the order of the spectrum colours, we were under the Thompson. This metal at the temperatures employed is impression, even after much reading, that the subject was soon covered with a film of suboxide, and the play of

colours on its surface, unavoidably produced by variation Stahl and followers made note of the chameleon-like of temperature, can scarcely fail to give a wrong im. behaviour of certain metallic oxides, and Schönbein,* who pression of the change in the metachrome under obserstudied the subject, inferred from his observations that vation. heat imparts a darker colour to metachromes, and gene- The behaviour of mercuric oxide calls for a few remarks, rally red or brown. Sir David Brewstert called attention since here decomposition was observed at a comparatively to the change in the absorption-bands of nitric peroxide low temperature. Resolution commenced at 230° to when that body is subjected to heat, and twenty years 232° C., 260 m.m. bar., metallic mercury being deposited later (1857) Gladstone made observations on the change in the cooler parts of the containing tube as a scarcely of colour in salt solutions upon elevation of temperature. perceptible fiim, in which globules could only be made out He observes that whilst some really exhibit colour change, with the aid of a lens.

Table 1.-METACHROMATIC CHANGES.
Metachrome.
Normal Colour.

Change.
Mercuric oxide

Orange-yellow. (In N, air, and CO2.) Orange, red, and brown. Zincic oxide

White

(In N, air, and CO2.) Yellow and orange. Cinnabar

Scarlet

(In sealed tube.) Dark scarlet and puce (240° C.). Mercuric iodide

16° C., Red

Dark red.
140° C., Yellow (In sealed tube.) Orange and red.

(The same change under paraffin.) Manganous oxide..

(In hydrogen.) Greenish yellow. Plumbic oxide

Yellow

(In air and CO2.) Orange and red. Chromic oxide

Green

Yellow, and when cooling just after the 'glow' of a

bluish cast. Manganates of potash and soda

Perceptibly greener. Red oxide of manganese

Reddish brown Nearly black. Thallious iodide

Yellow

Orange-yellow, changes suddenly to orange-red. Sesquichloride of thallium .

Yellow

Orange and orange-red. Thallious bromide

Yellowish white Yellow and orange-yellow. Terchromate of thallium

Orange-red

Red and dark red.
Neutral chromate of thallium Orange-yellow Orange, red, and deep red.
Metaborate of copper

Blue

Green and greenish yellow. Porcelain

White

Yellow.. Suboxide of copper glass

Scarlet

Blackish red and black. Chromate of barium

Yellow

Orange. of lead..

Orange

Brick-red and black-red. Plumbic iodide

Orange-yellow Orange and red. Argentic iodide

Yellowish white Greener cast; and from 1050*—116° C. to fusing-point,

orange, red, and dark red. phosphate

Yellow

Orange and reddish brown. Potassic dichromate

Dark red.

* Point of maximum density (Rodwell). * Gmelin's "Chemistry," vol. i., p. 238.

Journal of the Franklin Institute, October, 1871, and CHEMICAL + Proceedings of the Royal Society, vol. cxxvii., p. 247. 1 News, vol. xxiv., pp. 177 and 188. Phil. Mag., vol. xiv., p. 423.

§ Proceedings of the Royal Society, No. 161, 1875.

Greenish grey

Bluish green

..

..

..

Red ..

76
Metachromatism, or Colour Change.

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August 25, 1876. To ascertain the more intimate nature of the change in The position of all the members, save the lowest three, these anhydrous bodies was a work of some difficulty is determined by experiment. That white has the position until the following simple expedient was devised :-Crys- we give it seems probable because-(1) by experiment talline metachromes were used. The finely-powdered with the ZnO class of metachromes it plainly occupies a body was placed upon the concave side of a watch-glass, position at the opposite end of the scale to orange and and pressed into a thin layer by the convex side of a red; (2) the behaviour of blue and green metachromes second glass. The spectrum of the transmitted light precludes its being placed between these two colours ; being obtained at the normal temperature, the temperature and (3) it is the direct opposite of black. Violet and was now raised, and a second spectrum obtained for com- indigo are only placed in the scale provisionally to make parison. Such a comparison for potassic dichromate we up the spectrum colours, as there are no experiments to have in the following figure :

warrant their being so placed.
бE

The metachromatic scale may be looked upon as showing
F
D CB

the colour effects of expansion on the one hand, or of
contraction on the other. And were it possible to reach
the absolute zero of temperature we should probably have
there colours of the white end of the scale.

II. Theories of Metachromatism.
It will be observed that upon elevation of temperature
the absorption-bands at the ends of the spectrum widen

Stahl and followers connected colour-change with the out, and ihe more refrangible increment of absorption is varying amounts of phlogiston a body was supposed to nearly double that of the less refrangible. From the last contain when being heated. Schönbein supposed the observation the spectral order of change characteristic of metachromes underwent what he termed an incipient demetachromatism follows as a natural consequence, the composition,-i.e., one of the elements was supposed to less refrangible constituents of a body's reflected light be held in a peculiar state of combination whilst hot, and being, so to speak, more persistent than the more re.

to regain its normal position upon cooling. Mercuric frangible during elevation of temperature.

oxide, for example, was thought to assume the brownIn a certain class of bodies, like Zno, the spectrum black colour of the suboxide from losing a part of its order of change is not so evident, from the fact that white oxygen, which was retained in a peculiar manner in the has strictly no place in the spectrum. To this class be

mass. Now mercuric oxide, from being an exception to a longs such bodies as TiO2, Ta2O5, MoO3, Sb2O3, Sb2O4, law wrich we shall presently state, appears to favour Snöz, white porcelain, lead glass, colourless solution of Schönbein's hypothesis. When we think, however, over ferric nitrate, and nitric peroxide at low temperatures, whilst it is in the deep orange state, we see that no sub

the fact that this oxide is partially decomposed at 232° C., which, being white or colourless, become yellow upon oxide is really formed. elevation of temperature. In another and larger class, of which borate of copper and plumbic oxide may be taken

It is difficult to see how the hypothesis can apply in the as examples, the spectrum order is very evident. Both case of borates, phosphates, and silicates. That it does classes alike owe their change to increased absorption of not hold with binary compounds will be evident after a light, with elevation of temperature; and a white body, consideration of the following law, which we discovered if the temperature be raised high enough, may be made during our study of this subject :-In a series of anhydrous to pass not only from white to yellow, but also from yellow binary compounds of the same two elements, those which to orange, and thus the line of demarcation between the have the highest amount of the basylous element have the two classes is broken down. Reflecting upon these facts, most refrangible colours, and, vice versâ, those which have we see that it is possible to arrange the colours in order the least amount of the basylous element have the least this we have done as follows:

refrangible colours. The table below illustrates this,

and it will be found to hold good in many more anhydrous Metachromatic Scale.

series than are given here. Black.

From the table it is evident that decomposition Brown.

(incipient or complete) of any particular compound would Red.

give us more refrangible colours instead of the less Orange.

refrangible, which is the result of elevation of temperature, Heating, or Yellow.

Cooling, or -e.g., incipient decomposition of the brown PtCle would
Expanding. Green.

Contrading. give us the more refrangible green PtCl2.
Blue.

It is not our intention here to enter minutely into
Indigo.

Messrs. Houston and Thompson's theory: the reader is Violet.

therefore referred to their paper in the CHEMICAL News White or colourless.

(vol. xxiv., pp. 177 and 188). We note that (1) no men

Black ..

Table II.-SHOWING COLOUR RELATIONS OF ANHYDROUS BINARY COMPOUNDS.
Metachromatic

Each Series arranged Vertically.
Scale.
Ausz
InO2 CuO MnO2 NizO3

Co304

Pb20 (?)
Brown.. Auzs

Cuss
Mn0,&

PbO2
Mn203
PCI,
Red D

Bizos
Cuzo

AuClz Hg12 CrOz Pb304 Fe2Os
Orange
BizO3 In2O3

AuCl Hg213 Yellow

РЬО Feo Sbzos Green .. PiCl2

In Os

MnO Nio Auzo Cd20 Hg212 COO Cr203 Blue

Cus Indigo..

(Ind. copper) Violet ..

Crecio
White or
ŚCI, Inyo,

Sb2O, Grey (Metal)