trated in a novel manner. He introduced phosphorus, and copper leaf, also mercury, at a high temperature, into the gas, which exhibited the phenomenon of spontaneous combustion. An ignited taper was also introduced into the chlorine, when it burned with a red flame, but was extinguished on being withdrawn into the atmosphere, while it rekindled, though it did not burn with the same intensity, on its re-introduction into the gas.

The lecturer confessed himself unable to account for this singular fact. In some incidental observations on hydrogen, Mr. Murray noticed an experiment too often attempted with this gas, which was highly dangerous, indeed he knew of none more So. A common quart bottle was emptied, and a portion of glass tube passed through the cork, after the ingredients for evolving the gas had been cast into the bottle. The gas was then lighted as it escaped; but it was ten to one that the bottle would be shattered to atoms in the attempt, and the parties trying the experiment dangerously wounded. The gas might be taken into the lungs and respired for a short time, when it would exhibit the remarkable phenomenon of changing the voice. Reverting to the more important subject of chlorine gas, he observed that it was employed either alone, or in combination with lime or magnesia, to bleach linen or calico, and even paper, the latter not only in its pulpy state, but also after it had been manufactured.

He was

sorry for this, from the conviction he entertained that many valuable manuscripts, and even printed works, would ere long become a carte blanche. He could point to a valuable library in Yorkshire, consisting of about 30,000 volumes, collected by the proprietor at an immense cost, many of the works in which would have mouldered into dust before the lapse of half a century, from the circumstance that the paper on which they were printed having undergone the process of bleaching by chlorine; while owing to the same circumstance, many valuable deeds and documents in the country were in a fair way to destruction. His audience were, no doubt, aware that every thing now-a-days was converted into paper. He could show them specimens of paper in his own collection made from the roots of trees, from grass, from saw-dust, from husks of corn, from thistle down, from cotton waste, from potato stalks, and, to crown the catalogue, it was not many years since Mr. Mallett gravely proposed at the meeting of the British Association in Dublin, that the turf bogs of Ireland should be converted into paper. There was a curious circumstance connected with paper, the right cause of which was little suspected. It was this:--

They found that the ink was always com plained of, and hence they had a host of competitors offering all kinds of ink as nostrums for the evil. It was not, however, the ink that was in fault. The ink made at the present day was as good or better than ever; it was the paper that was the cause of the mischief. Let them take for in stance two sheets of paper, one of good quality, the other of that description which was sold at about 4d. a quire. Let them write with the same ink on the surface of both papers, and they would find while one was a jet black and maintained its colour, the other became quite brown, and the paper on which it was written would shortly moulder away. Mr. Murray also mentioned the fact that sulphate of copper was not unfrequently used in making particular kinds of ink. In mending the quill pen used in writing with the ink, the sulphate seized upon and blunted the fine edge of the knife, and destroyed in a very short time the point of the steel pen. These facts, he observed, spoke for themselves. In re ference to the bleaching properties of chlo. rine, the lecturer exhibited some novel experiments. He first wrote the word ** chlorine" with common ink on a slip of paper, which he introduced into a bottle containing the gas, and the colour in the space of a few seconds was discharged, leaving the paper as from stain or mark as it was before it had been written upon. He next took a strip of blue calico, one end of which he dipped in water, (the presence of moisture being necessary to the development of the bleaching powers of the gas,) and plunging it into the chlorine, the colour of that portion of the cloth brought into contact with the water, was effectually discharged, while in the dry portion, although equally exposed to the influence of the gas, the colour remain. ed. Mr. Murray next directed attention to one of the most important points connected with the use of chlorine,-namely, its powers as a disinfecting agent. In applying disin fecting means and measures, he contended nothing could be rationally depended upon, short of the decomposition and consequent destruction of the noxious miasm, and nothing was chemically known to effect this on the requisite practical scale but nitric or nitrous acid and chlorine. It was by this means that the Chevalier di Gimbernat succeeded in staying the plague in Andalusia in 1801. By the admixture of nitric and mu riatic acids chlorine was formed; it might also be liberated from the chloride of lime or-soda by the addition of sulphuric acid; heat, in these cases, would render the evolution of the gas more complete. For the use of families, where typhus or scarlet

fever prevails, Mr. Murray recommended the following simple method, which he be lieved would prove effectual in staying the progress of infection. To a tea-cup, containing a small quantity of peroxyde of manganese, a fluid ounce or more of muriatic acid should be added. These ingredients should then be mixed by means of a rod, or any other substance, not metallic, when the cup and its contents should be placed in a soup plate containing water about milk warm. This might be placed in some convenient angle of the room of the patient, or the passage leading to it, and if that was found too powerful, a saucer or plate laid over the cup would be all that was required, while the power of the gas might be increased at pleasure by removing this temporary covering, or adding fresh portions of acid or of oxyde.

CLARIDGE'S PATENT ASPHALTIC MASTIC

COMPOSITION.

This invention consists in the combination by heat of two substances into a mastic cement or composition: one substance being a natural compound. consisting principally of carbonate of lime and bitumen, with a small portion of aqueous and other matter, and commonly known by the name of asphalte or asphaltos or calcareous asphalte, asphaltic mineral, or asphaltic rock, or asphaltic stone. It is found at Pyrimont, near to Seyssel, in the department De l' Ain, in the kingdom of France, and in other parts of the Jura Mountains, and in other places, in great abundance. The other substance is bitumen or mineral or other pitch. To make the composition the patentee directs you to proceed as follows:-Take the asphalte in its native state, as it is extracted in masses from the mine, and reduce it to powder; it may be reduced to powder solely by mechanical means, but the process is facilitated by heat, by placing the masses in a furnace or oven, the bottom of which is made of plateiron; in about half an hour, by the application of a brisk fire, the asphalte falls or is readily reduced to powder. The asphalte is then passed through a sieve, the meshes of which are about one-fourth of an inch square; it is then in a fit state to be mixed with the bitumen or mineral or otber pitch. The bitumen is freed from its extraneous matter in the ordinary way.

Take about ninety-three pasts of asphalte reduced to powder, and passed through a sieve as directed. to about from seven to ten parts of bitumen or mineral pitch. The quantity of bitumen intended to be used is first placed in a melting cauldron or furnace, and when it is dissolved the powdered as

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phalte is added gradually; the mixture is kept carefully stirred in order that it may not be burnt, and also that the asphalte and bitumen may be perfectly amalgamated. The mixture is kept over the fire, carefully stirred, until the whole is thoroughly combined and is nearly fluid, and then kept over rather a slow fire until the mixture is nearly in a state of ebullition, it then gives out a light white smoke in jets, and it is fit for use. When other asphalte is used, instead of the asphalte of Pyrimont, the quantity of bitumen to be added, will vary according to the particular nature of the asphalte, and the proper quantity will easily be found by trial. When bitumen or mineral, or other pitch than that from the neighbourhood of Pyrimont is used, the precise proportion will easily be determined also by trial.

In applying the cement or composition to paving, add to about every 200 pounds weight of the nearly fluid mastic cement, about half a bucket full of very small, clean, and hot gravel or sand; this is carefully stirred up with the mastic, and as soon as it is sufficiently fluid, that is, as soon as the mastic begins to give out the light white smoke previously described, it is fit for use. It may then be run into moulds, and remain until cold, when it will form blocks or slabs, which may be laid upon any proper foundadation. These blocks or slabs are cemented together by pouring the fluid mastic cement between the interstices of the blocks or slabs. Sometimes a thin coating of mastic cement is spread over the foundation, and the blocks or slabs are imbedded therein, in such case the cement is also poured in between the interstices. If it be desired that the pavement should be ornamented so as to represent mosaic or other work, the process of forming the blocks or slabs is as follows:

First, a large flat surface is formed, either of wood or plaster, upon which the required pattern is drawn. This surface, or a portion, is enclosed with iron bars of the intended thickness of the slab; over this surface, a thin coat of transparent glutinous size is spread; as the following work advances, pebbles of various colours, pieces of porcelain-ware, earthen-ware, glass, or other materials, of the required forms and colours, are deposited upon their allotted portions of the patterns, either to represent foliage or fret-work, or any other device. By means of the weak size, they are very lightly retained in their places, and the mastic cement or composition, either mixed with fine gravel or sand, or unmixed, is poured into the space enclosed with iron bars. This mastic cement or composition fills up the interstices between the pebbles, pieces of porcelainware, earthen-ware, glass, and other ma

terials, and forms with them a hard slab, the bottom thereof being the surface or part to be exposed. The slabs thus formed are cemented together in the same manner as before directed.

To form ways or paths proceed thus. Upon a proper foundation place two flatiron bars parallel to each other at a convenient distance from each other, say, from three to four feet-these bars are of the thickness to which the mastic cement or composition is intended to be spread, usually about half an inch thick; between these bars, the fluid mastic and fine gravel or sand is poured and spread, and the surface made regular and uniform by passing a thick piece of wood, with one straight edge, backwards and forwards upon the iron bars. Upon this surface, whilst still in a semi-fluid state, sift fine hot gravel, which is to be beat into the mastic with wooden stampers. When the mastic is set, the operation is repeated until the surface required for the way or path is covered. As the operation proceeds, the surface of the cement already set, renders the use of the iron bars unnecessary.

For road-making, superficially; upon the surface of a road formed of the usual materials, in the usual way, and the bottom of which has undergone the usual preparation, pour mastic cement or composition thereon, either with or without fine gravel or sand, heated just so as to give out the light white smoke, and it then forms with such stones, a hard and compact surface; or another way is to apply the mastic cement under the hard materials, and in which case spread a thin coating of the cement, either mixed with fine gravel or sand, or not, between the substratum and the hard materials, for the purpose of preventing the hard materials being injured by the land-springs.

In applying the cement for the purpose of covering buildings; cover the roof with canvass,similar to that used by paper-hangers, stretched tolerable tightly, and upon this canvass spread a layer of the fluid mastic cement, to about the thickness of fourtenths of an inch, and upon the surface of the mastic, when the same is in a semi-fluid state, sift gravel previously heated; and, as the mastic sets, beat the gravel into the surface of the mastic with flat wooden stampers, about fifteen inches long and nine inches broad, until the gravel is incorporated into the substance of the mastic.

The process of applying the mastic to the lining of tanks, reservoirs, and other similar purposes, is very similar to that pre

viously described. In such linings, no gravel or sand is used with the said mastic, but a coating is applied whilst the mastic is of the heat, when it just begins to give out a white light smoke. For the bottom surface of tanks or reservoirs, a simple covering of the mastic is sufficient; for the sides of such tanks or reservoirs, the face of each brick which is intended to be inwards and exposed to the water, is first covered with a thin coat; this is done by laying the bricks side by side on a level ground, as if they were to form a pavement, then the fluid mastic is thinly spread over their whole surface; as soon as it begins to set, which is in a few seconds, and before it becomes hard, the blade of a large knife is passed between the bricks, cutting the mastic through, at the same time the process leaves each brick with one face covered with the mastic cement. This done, the walls or sides of the tanks or reservoirs are built, and each brick is set in fluid mastic, instead of calcareous mortar or cement; and for greater security a space of about half an inch is left between the inner and outer bricks, which form the side-walls of tanks or reservoirs: this space is filled up with the fluid mastic, as the brickwork advances; this is the process usually adopted.

NOTES AND NOTICES.

Daguerreotype.-M. Arago has lately communicated to the Secretary of the Academy of Sciences at Paris, some photogenic representations of the principal buildings of Rome, made with the Daguerreotype, by one of the workmen of M. Lerebours, the celebrated optician, sent thither for that purpose. M. Arago remarked that this was a proof of how little the apparatus in question stood in need of being invariably placed in the hands of a man of science. The views were very distinct and beautiful.

Death of Mr. Oldham, C.E.-We regret to have to announce the death of this ingenious mechanic and talented engineer, on Friday night, the 14th instant, of internal hæmorrhage. Mr. Oldham was engineer of the Bank of England, having previously held the same office in the Bank of Ireland. All the beautiful and complicated machinery used in both establishments for the preparation of the plates, the engraving, printing, numbering, and other operations connected with the manufacture of the notes, were designed and executed by him, and evinced a first-rate genius in mechanical computation and combination. Mr. Oldham has left a very numerous family, no less, we believe, than seventeen children. His eldest son now holds the office of engineer to the Bank of Ireland.

Egypt.-Machines have been brought from England to drain the marshes at Alexandretta, where the stagnant waters fill the country with malaria. The same cause propagates fever in the Egyptian army at Marasch, Adana, and other places. The hospital service is very badly arranged.