the fumes, even the instant after the explosion.

Further Experiments at Wharncliffe Colliery.—On Tuesday, October 25, some very interesting surface trials were arranged with great care by Mr. Walker. An old boiler flue was placed vertically, and closed at top by means of a removable wooden cover, the interior space being about 72 cubic feet. A temporary gasometer had been arranged at a suitable distance by means of a paraffin cask having a capacity of 6 cubic feet suspended inside a larger cask, and by this means the boiler was charged with a highly explosive mixture of gas and air in the proportion of 1 to 12.

1. A charge of gunpowder was placed in the closed end of a piece of gas pipe, and strongly tamped, so as to give the conditions most unfavorable to the ignition of the firedamp. It was, however, ignited, and a loud explosion produced, which blew off the wooden cover and filled the boiler tube with flame.

2. Under the same conditions as to firedamp, a charge of roburite was placed on a block of wood inside the boiler, totally unconfined except by a thin covering of coal dust. When exploded by electricity, as in the previous case, no flame was produced, nor was the firedamp ignited.

3. The preceding experiment was repeated with the same results.

4. A charge of blasting gelatine, inserted in one of Settle's water cartridges, was suspended in the boiler tube and fired with a fulminate of mercury detonator in the usual manner. The gelatine did not, however, explode, the only report being that of the detonator. After a safe interval the unexploded cartridge was recovered, or so much of it as had not been scattered by the detonator, and the gelatine was found to be frozen. This fact was also evident from an inspection of other gelatine dynamite cartridges which had been stored in the same magazine during the night. This result, although not that intended, was most instructive as regards the danger of using explosives which are liable to freeze at such a moderate temperature, and the thawing of which is undoubtedly attended with great risk unless most carefully performed. Also, the small pieces of the gelatine or dynamite, when scattered by the explosion of the detonator, might cause serious accident if trodden upon.—Engineering.

THE MECHANICAL REELING OF SILK.

When automatic machinery for thread spinning was invented, English intelligence and enterprise were quick to utilize and develop it, and thus gained that supremacy in textile manufacture which has remained up to the present time, and which will doubtless long continue. The making of the primary thread is the foundation of all textile processes, and it is on the possibility of doing this by automatic machinery that England's great textile industries depend. The use of highly developed machinery for spinning cotton, wool, and flax has grown to be so much a part of our conception of modern life, as contrasted with the times of our grandfathers, as often to lead to the feeling that a complete and universal change has occurred in all the textile industries. This is, however, not the case. There is one great textile industry—one of the most staple and valuable—still in the primitive condition of former times, and employing processes and apparatus essentially the same as those known and employed before such development had taken place. We mean the art of silk reeling. The improvements made in the production of threads of all other materials have only been applied to silk in the minor processes for utilizing waste; but the whole silk trade and manufacture of the world has, up to this time, been dependent for its raw silk threads upon apparatus which, mechanically speaking, is nearly or quite as primitive as the ancient spinning wheels. Thousands of operatives are constantly employed in forming up these threads by hand, adding filament by filament to the thread as required, while watching the unwinding from the cocoon of many miles of filament in order to produce a single pound of the raw silk thread, making up the thread unaided by any mechanical device beyond a simple reel on which the thread is wound as finished, and a basin of heated water in which the cocoons are placed.

Viewed from any standpoint to which we are accustomed, this state of things is so remarkable that we are naturally led to the belief that there must be some special causes which tended to retard the introduction of automatic machinery, and these are not far to seek. The spinning machinery employed for the production of threads, other than those of raw silk, may be broadly described as consisting of devices capable of taking a mass of confused and comparatively short fibers, laying them parallel with one another, and twisting them into a cylindrical thread, depending for its strength upon the friction and interlocking of these constituent fibers.

This process is radically different from that employed to make a thread of raw silk, which consists of filaments, each several thousand feet long, laid side by side, almost without twist, and glued together into a solid thread by means of the "gum" or glue with which each filament is naturally coated. If this radical difference be borne in mind, but very little mechanical knowledge is required to make it evident that the principle of spinning machinery in general is utterly unsuited to the making up of the threads of raw silk. Since spinning machinery, as usually constructed for other fibers, could not be employed in the manufacture of raw silk, and as the countries where silk is produced are, generally speaking, not the seat of great mechanical industries, where the need of special machinery would be quickly recognized and supplied, silk reeling (the making of raw silk) has been passed by, and has never become an industrial art. It remained one of the few manual handicrafts, while yet serving as the base of a great and staple industry of worldwide importance.

There is every reason to suppose that we are about to witness a transformation in the art of silk reeling, a change similar to that which has already been brought about in the spinning of other threads, and of which the consequences will be of the highest importance. For some years past work has been done in France in developing an automatic silk-reeling machine, and incomplete notes concerning it have from time to time been published. That the accounts which were allowed to reach the outer world were incomplete will cause no surprise to those who know what experimental work is—how easily and often an inventor or pioneer finds himself hampered by premature publication. The process in question has now, however, emerged from the experimental state, and is practically complete. By the courtesy of the inventor we are in a position to lay before our readers an exact analysis of the principles, essential parts, and method of operation of the new silk-reeling machine. As silk reeling is not widely known in England, it will, however, be well to preface our remarks by some details concerning the cocoon and the manner in which it is at present manufactured into raw silk, promising that if these seem tedious, the labor of reading them will be amply repaid by the clearer understanding of the new mechanical process which will be the result.

The silkworm, when ready to make its cocoon, seeks a suitable support. This is usually found among the twigs of brush placed for the purpose over the trays in which the worms have been grown. At first the worm proceeds by stretching filaments backward and forward from one twig to another in such manner as to include a space large enough for the future cocoon. When sufficient support has thus been obtained, the worm incloses itself in a layer of filaments adhering to the support and following the shape of the new cocoon, of which it forms the outermost stratum. After having thus provided a support and outlined the cocoon, the worm begins the serious work of constrution. The filament from its silk receiver issues from two small spinnarets situated near its