Now, however, we understand that the people of Dax aim at completing this work of vandalism, and that, by means of very grave misrepresentations, they have obtained a kind of surreptitious license to destroy all that still exists of the Roman remains. It is to be hoped, however, that they will not succeed in their design; for M. de Caumont again stands forward, and has published an energetic statement of the case in the new number of the "Bulletin Monumental" (just published), and it is hoped that the voice of antiquarian science will be raised as earnestly and listened to as readily as on the former occasion. It is very desirous that some means might be devised to put this interesting historical monument out of the reach of future danger. T. W.

PROGRESS OF INVENTION.

LOCKETS. Mr. William Gilbert, of Birmingham, has invented a method of making lockets which he describes as follows:-I make the frame carrying the miniature or other article to be held in the locket turn out of the locket at the side of the case, somewhat after the manner in which the blade of a pocket knife turns out of the handle, instead of making the locket open by a lid, similar to the lid of a box. I make the case of the locket out of one piece of sheet-metal folded at its middle, the blank having the figure of the two sides of the the case joined together by a narrow strip or band. I also make the frame of the locket of a blank having the figure of the two sides of the frame joined by a band or strip at the middle. When doubled at this band, the frame is fixed in the case by means of the suspending ring, which passes through a hole in the case and frame opposite or nearly opposite the bands where they are folded. The frame of the locket turns upon this suspending ring as on a centre. The folded band of the case constitutes a stop, against which the folded band of the frame shuts or abuts, and by which the motion of the frame is limited. The folded part of the frame also constitutes a catch, by means of which the frame may be drawn out of its case by the application of the thumb or finger nail.

DECOMPOSING THE SULPHURETS OF IRON CONTAINED IN ORES, COAL, ETC. -M. Edmond Grandidier, of Paris, has invented a process for effecting this object. It consists in the application of heat and compressed air, or of heat and compressed steam, to the decomposition of the sulphurets of iron contained in various mineral products, such as ores, coal, coke, and other substances. A cylinder is made sufficiently strong to bear the required pressure, into this the steam is forced by a pump, or passes direct from the boiler. The pressure required for desulphurisation being generally about two atmospheres. When the operation is carried on in

the vicinity of blast or other furnaces, the waste heat of the latter may be utilised for the purpose of this invention. Among the more important applications of this invention, may be noted the desulphurisation of the coke used in the manufacture of iron and other metallurgical operations.

GLOVE FASTENING.-Upon the thumb side of the glove, at the place where the button hole is usually formed, a plate is sewn; this plate has two apertures, one of which is used for securing it to the glove, the other forms an eye or loop, to serve instead of a button hole. On the side of the glove opposite to the thumb, a lace or tape is attached, the other end of which is carried under the rear end of a hooked plate, which forms the clasp, then up through a slit in this plate, and down through another slit, coming out again at the rear end of the plate or clasp, and terminated by a tassel, this tassel coming out underneath the edge of the clasp holds both in position. The other end of this clasp or plate terminates in a hook to take into the eye, which serves as a button hole. Gloves furnished with this arrangement can be unfastened in two ways, either by raising the plate or clasp, and drawing the lace, or by simply releasing the hook from the eye. The tape or lace can be made of elastic material. These fastenings may be removed from one glove to another, by making the glove with two button holes, and putting on the fastening two buttons, so that the eye and tape instead of being sewed or riveted may be fastened to the glove by buttoning. The inventor of this fastening is M. Theodore Deschamps, Rue de Choiseul, Paris.

TREATING CAST IRON.-PRODUCING STEEL, ETC.-Mr. Heaton, an account of whose process for the purification of iron from carbon, sulphur, and phosphorus has already been given (STUDENT, vol. i. p. 74), has patented two improvements, which have lately received the Royal Seal. The first of these relates to the treatment of pig-iron, and it consists in subjecting the iron, contained in a suitable furnace or converter, to the action of nitrate of soda or potash, or other suitable nitrate, with or without the employment of a blast, in such quantities as that the impurities in the pig or cast-iron shall be partially or wholly removed with the abstraction of the smallest quantity of carbon practicable, the object being to purify the pig-iron, and not to convert it into steel or malleable iron. The second patent is for the production of steel, and consists in the employment, for this purpose, of the purified or converted pig or cast-iron, or the combination of iron and carbon, such as results from the action of nitrate of soda, or nitrate of potash, upon cast-iron when in a molten state, either alone or in conjunction with a blast, and contained in a converter, such as is described in a former specification, or in any other converter or furnace together with metallic iron, such as sponge-iron, scrap, bar, or any other form of metallic or malleable iron. The product resulting from the action of nitrate of soda or potash upon pig or castiron, as before-mentioned, is to be melted in a suitable furnace or crucible,

and metallic iron is to be added to it, and to be dissolved in it, or alloyed with it, until the molten metal shall have attained such a composition as may be required, either for the production of steel, or of other compounds. of iron and carbon resembling steel.

MANUFACTURING AND APPLYING GAS AND VAPOUR.-The first part of this invention consists in forcing air through, or over hydrochloric acid, for the purpose of taking up hydrochloric acid gas with the atmosphere, for applying it in the manufacture or refining of iron, steel, copper, or nickel, and the like, while such metals are in a fluid or molten state The second part consists in causing atmospheric air, in a cold or heated state, to be forced through or over hydrochloric acid, and then through wood, naphtha, or mineral turpentine, or volatile spirit, for the purpose of taking up hydro-carbon vapour. This mixture is then forced through or over the metals while they are in the molten state, during the manufacture or refining thereof, for the purpose of taking up sulphur, phosphorous, etc., or other impurities which the metal may contain. Mr. James Webster, the inventor of this process, also applies it to articles of wrought-iron, wholly, or partially finished, which require to be case hardened on their surfaces. He places such articles in a closed receptacle, which is to be heated to a red heat, and his mixture of air, and other gases or vapours, is passed into the receptacle, the time varying according to the desired thickness of the hardened skin.

MAKING AND APPLYING ANILINE BLACK, by Mr. James Higgin, of Manchester.-Commercial aniline is employed: this generally contains toluidine. The first part of the invention consists in making a solution of aniline by mixing it with a solution of a metallic salt, such as the chlorides of iron, of tin, or of chromium. In some cases, the metallic base of the salt employed is precipitated, and chloride of aniline remains in solution, and in some cases the metallic base is only partially precipitated, whilst in others, no precipitation takes place, and a compound solution is formed. Along with the above-mentioned aniline solutions, may be used the other materials generally employed in making aniline black, such as chlorate of potash, and sulphide, or other copper salt in use for this purpose. Sulphates of the above metals can be used instead of chlorides; but in this case, as sulphate of aniline is produced, some alkaline chloride must be added to the colour. By the second part of the invention the use of the salt of copper, termed, disulphocyanide, either in paste or powder, is adopted. This salt of copper can be used either to take the place of the sulphide of copper, usually employed, the other materials being as at present used; or a new black may be made with one or more of the aniline solutions above described, the disulphocyanide of copper, and chlorate of potash. The treatment, after printing in these blacks, may be that usually employed.

E

CORRESPONDENCE.

MEASURING HEIGHTS.

To the Editor of the Student.

MY DEAR SIR,-On occasion of a visit lately to some of our English cathedrals and Abbeys, I was desirous of ascertaining the height of the columns and arches. Unfortunately, I had not provided myself either with my pocket sextant, or any angular instrument. I therefore folded a piece of paper, so as to produce an angle of 45'; and by looking along two of its edges, arrived at a very rough approximation to the height. Since then I have contrived the instrument for the above purpose, of which I enclose a sketch, of the full size, kindly furnished by P. O. Hutchinson, Esq. The principle is the same as that of the optical square or sextant, and its size adapted to the waistcoat pocket. One which I have made could be contained in the top of a pencil case; but this has no provision for adjustment. The description is as follows:-Two plane mirrors, A and B, are fixed in a brass frame, C, which springs at D. A screw at E furnishes the means of drawing the mirrors nearer to each other, and thus of adjusting them. The mirrors are set an angle of 22° 30'. This by reflexion of course becomes 45°. The silver is removed at the top of B as in the horizon mirror of the sextant. Looking, then, over the edge of A, and through B, the top of an object reflected therefrom is seen on B, and at the same time a mark (previously made on the base of the object, and equal to the height of the eye) may be brought into coincidence with it, by varying the distance from the base, which distance will then be equal to the height of the object above the eye. The height of the eye added to this of course gives the altitude above the ground. F is a piece of brass filed very exactly to an angle of 22° 30', the occasional insertion of which between the mirrors, furnishes a ready means of adjustment by the screw E. Instead of the brass frame and screw, I have also made the instrument, simply by separating the mirrors by stout cardboard cut to an angle of 22° 30', and cemented to them with liquid glue, all being then covered with leather; but here there is no means of adjustment. If required, a sight-hole may be pierced at the upper part of A, a corresponding portion of the silver being there removed.*

In a subsequent letter Mr. Heineken says:-"The mirror being fixed in a firm frame, without spring, as near to the angle of 22° 30' as possible, let the point of the frame of the front mirror be sprung at the confining edge, and at the back of the mirror let there be inserted a free plate of thin brass, against this let a screw press, tapped in the back of the frame itself. This, in fact, is the plan adopted for adjustment in sextants.

The following method of subdividing the graduations of aneroids, etc., which I have contrived, may be of service to some of your readers. On a small plate of glass, from five to ten lines radiating from a centre, are ruled with a diamond point. If this is placed on the covering glass of the aneroid, it may be so adjusted as to subdivide any scale within the limits of the radiating lines, a lens, of say two or three inches focus, being used for reading both at the same time. The lines in fact form a kind of universal dividing scale.

I enclose one of the pieces of ruled glass for your trial and acceptance. For easy reading the lines should have been somewhat coarser.

Believe me, my dear Sir,

Sidmouth, Feb. 26, 1869.

Yours truly,

N. S. HEINEKEN.

We have to thank Mr. Heineken for the ruled glass, which is easily used as he describes.-ED.

LITERARY NOTICES.

INTRODUCTION TO SCIENTIFIC CHEMISTRY.

Designed for the use of

Schools and University Matriculation Examinations. By F. S. BARFF, M.A., Christ College, Cambridge; Assistant to Dr. Williamson, Professor of Chemistry, University College. (London: Groombridge and Sons.)— The great change which has taken place in theoretical chemistry has created a necessity for new text books, and Mr. Barff has ably supplied a want urgently felt in all good schools. Those who are not acquainted with the new chemical views, will not readily understand their bearing upon practical teaching. They will be apt to argue that the facts remain the same, and that the hypotheses based upon them are of comparatively little consequence, or at any rate, only concern very advanced students. Such arguments are, however, exceedingly fallacious. The new theories have grown out of a more exact and extended observation of the actual conduct of bodies under different conditions, and they have led to a wonderful improvement in the mode in which chemistry can be taught, and in which it is taught in those schools (not too many) which keep pace with the times. No good teacher will torment his pupils with theories they cannot understand. All sound teaching in physical science must begin with facts, and the reasoning dependent upon them ought not to be introduced until the pupil knows enough to follow it in an intelligent way, and can discriminate between those portions of theory that are well established, and those which are more or less doubtful guesses at truth. The great art of teaching chemistry well, consists in marshalling the