The temperature of No. 1 had been above 600°. The paper, cotton batting, and box were charred; the parchment and sealing-wax were destroyed. The paper,

The temperature of No. 2 had been as high as 580°. cotton, and box were charred. The parchment and sealing-wax were destroyed.

The temperature of No. 3 had been 350°. Contents were much less injured than those of No. 1 and No. 2, but were still greatly discolored. The box was partially charred.

The temperature of No. 4 was 2870. The paper and cotton were discolored. The box thoroughly dried and shrunken somewhat, but not charred. The parchment was shrivelled and the sealing-wax melted.

The temperature of No. 5 had been 212. The parchment was somewhat shrivelled, and sealing-wax melted; but the paper, cotton batting, and box were uninjured.

In the safes filled with potash-alum, clay, and brick, - with ammoniaalum, salt and coke, and with sulphate of ammonia, salt, and coke, a coarse porous wall around the interior wooden case was preserved after the volatile matters had been driven out. In the cement safe, the cement retained about one-third of its water and the form perfectly. In the gypsum and water safe, the plaster retained its form. It had parted with about four-fifths of its water. (Strictly

From the foregoing, it is evident that in keeping the temperature down a given time, 74 lbs. of sal-ammoniac are inferior to 14 lbs. of water from potash-alum; and these inferior to 15 lbs. of water and sal-ammoniac, from ammonia-alum and salt; and these inferior to 13 lbs. of water from the cement safe; and these inferior to 16 lbs. of water from the plaster and water safe.

In the gypsum and water safe, 5 pounds of water were fixed in the setting, and 16 pounds were held by capillary attraction. These 16 were driven out at 212°. There remained 5 in combination, at the close of the experiment, to be driven out at the same temperature. In the cement safe, 6 pounds were fixed in the setting, and 133 pounds were held by capillary attraction. Of these 133, 13 were driven out at 2120. There remained but of a pound to be driven out at 212o. In the alum safe, there were but 8 lbs. expelled at 212°.

In summary-the gypsum and water safe lost 16 lbs. at 212°; the cement and water safe, 13 lbs. ; the alum safe, 18 lbs.

The water remaining to be expelled, at 212°, from the gypsum and water safe, was 5 lbs. ; from the cement safe, was 2 lb.; from the alum safe, was 0.

Not only was there no water to be driven out at 212°, but 63 lbs. had been driven out at much higher temperatures, the last at 5800.

A cement safe, as ordinarily made, set and dried, of these dimensions, contains a little more than half a pound of water to be driven out at 212°. In a plaster safe, set and dried, there would have been but 5 lbs. to be driven out at 212°. In an ordinary alum safe, there would have been less than 8; while in the gypsum and water safe, as here prepared, there were 21 lbs., which, by the process already described, might have been increased to 50 lbs.

1 A part of this loss was evidently due to the moisture in the clay.

The potash-alum safe lost altogether within 14 lbs. as much water as the plaster and water safe, but nearly one-half went out at temperatures from 212° to 580°, a range destructive to books and papers. The ammonia-alum and salt safe lost about 20 per cent. more of water and sal-ammoniac than the cement safe of water alone, and yet did not afford the same degree of protection, for the cement safe was heated only to 287°, while the ammonia safe was heated to 350°.

Experiment in a Furnace at a White Heat. Another experiment was undertaken with four safes of the capacity of one cubic foot each. Each contained a wooden box, enclosing a series of thermometers constructed to burst at given temperatures.

No. 1 contained cement, 64 lbs.; water, 3 lbs. This is cement containing the quantity of water which remains after the filling is set and dried.

This is a plaster

No. 2 contained plaster, 624 lbs.; water, 12 lbs. of Paris safe, containing twenty-five per cent. more than the quantity of water due to plaster set and dried.

No. 3 contained alum, 33 lbs.; pipe-clay, 33 lbs.; brick, 19 lbs. This safe, with a smaller proportion of alum, is in extensive use in this country.

No. 4 contained plaster, 28 lbs.; gelatine, 1 lbs.; water, 43 lbs. These safes were placed in the same reverberatory furnace in which the preceding experiment was conducted. There was this difference between the experiments: The first was conducted with a constantly falling temperature. This with a temperature carried from freezing up to a white heat, and there maintained for thirty minutes; and then permitted to cool down. At the end of the first half hour, Nos. 1 and 2, which were least exposed, were red hot; No. 3 was at low red, and No. 4 was dark.

At forty minutes, the condition was the same. At forty-two minutes, pronounced melting heat by the workmen, Nos. 1, 2 and 3 were red, but 4 still dark equally. At fifty minutes, No. 4 became low red, and No. 3 was burnt through and melted away at points nearest the fire. At 60 minutes, No. 3 was at a white heat, and No. 4 was red.

This white heat was maintained for thirty minutes, when the furnace was opened and cooled down sufficiently to examine the condition of the safes.

No. 4 was burned so as to crack a little on one side, but was not melted in any part. No. 3 was melted away from the top, front, and two sides. The side farthest from the fire, and bottom, were alone whole. No. 2 was scarcely less injured. The melting did not, however, extend so far down the sides. No. 1, which was further from the fire and sheltered by the other safes, was burned but not melted.

The fire was again raised to the melting point, the furnace closed, and the safes left in this heated chamber, slowly cooling down, from five o'clock in the afternoon till ten o'clock the next morning.

1 This elevated temperature, while there was still water in the cement, is manifestly due to the conducting power of the soapstone upon which the wooden box rested.

2 I employ the term gelatine as expressing in a single word the substance obtained by the action of boiling water from gelatinizable substances, like sea-weed, of the variety known as Iceland moss, or potato starch, or animal membranes, or from other similar vegetable and animal substances.

On opening the furnace, the appearances of the safes had not apparently changed since the examination at the close of the first experiment. The wooden boxes in Nos. 1, 2, and 3, had been destroyed. The temperature in No. 2 had been above 600°, and in Nos. 1 and 3, above 300°, but not to 600°, though probably not far below.

The wooden box in No. 4 was as fresh as when put in. The thermometer bursting at 150° was destroyed, but that bursting at 212° was sound. The heat had not attained to that of boiling water. It will be borne in mind that No. 1 is the ordinary cement safe, No. 2 is the ordinary plaster of Paris safe, No. 3 is the alum safe, and No. 4 the new safe. The first three were destroyed, while the temperature in No. 4 was, at the utmost, entirely within the range of safety to the books and papers.

Conclusions. 1st. It is evident that the protection against fire is mainly proportioned to the quantity of water the safe can give up to be carried away as steam, and not to the non-conducting quality of its filling.

2d. It is evident, further, that the protection against fire is not simply as the quantity of water that may be present in the composition for filling, but as the quantity of water that may be parted with unrestrained by chemical affinity, or WATER AS SUCH. The more powerful the chemical affinity resisting the escape of vapor, the more elevated must be the temperature at which it will leave, while the capacity of the escaping vapor to render heat latent or to absorb and carry it away will remain unchanged. The same quantity of water in combination in alum is not so serviceable in keeping down the temperature as when free.

3d. It is evident, further, that while the water, in its uncombined or natural state, must constitute a large part of the filling of a safe in order to make its protection against fire in the highest degree available, this water must be held in solid form so as to give strength to the safe; and the safe must be so constructed as to prevent the water from passing off by leakage or as vapor, to the injury of the books and papers, or to the lessening of the fire-proof qualities of the safe; and yet be so constructed as to allow, on the application of high heat, the most free escape of vapor from those points to which the heat is applied, without endangering the strength of the safe, or driving the vapor into the interior chamber of the safe; and withal so arranged as to permit freezing, without injury to the safe or its contents.

In a safe made in the light of the foregoing experiments, from 70 to 80 per cent. of the space appropriated to filling was occupied by water, and yet was exposed for a day and two nights to a temperature of zero without injury.

On exposure to fire the water is resolved into vapor first at the outer surface of the filling, and leaves the best non-conductor, according to the results of foregoing experiments between the water which remains and the heated metal of the exterior shell. At length, when all the water has been driven out as vapor, there remains the non-conductor of the whole thickness of the filling, to protect, as long as it may, the contents of the case.

THE GREAT BOSTON ORGAN.

During the past year there has been erected in the Music Hall, of the city of Boston, Massachusetts, an organ, which for absolute power and compass ranks among the three or four mightiest instruments ever built; and in the perfection of all its parts, and in its whole arrangements, challenges comparison with any the world can show. The instrument in question was built by E. F. Walcker, of Ludwigksburg, in the kingdom of Würtemburg, and was upwards of six years in the course of construction. Its cost was upwards of $50,000, and the case alone cost $15,000.

In itself, this organ may be described as really comprising five distinct organs, or systems of pipes, which are capable of being played on alone, or in connection with each other. Four of these are played upon by manuals or hand key-boards, and the other by pedals or a foot key-board. The lowest of the former controls the swell organ, the pipes of which, as in other instruments, are enclosed in a box (in this case, itself as large as many complete organs), and so arranged that it may be open or perfectly tight at the will of the performer, thus giving opportunity for light and shade in endless variety. This organ contains 18 registers or stops, with which are drawn on or shut off an equal number of ranks or series of pipes, all of which, or any of them separately or in combination, may be made to speak through the swell manual. Next above this is placed the key-board of the "great organ," as it is technically called. Here we have 25 registers, all of which connect with pipes on a large scale, and are the loudest voiced pipes in the whole organ. Here are the grand diapasons which form the foundation of the whole sound-superstructure, and the immense trumpets and clarions which ring out like a call to battle. Above the great organ manual comes that of the choir organ, which has 15 registers, and is in many respects the "great organ on a softer scale, but without the harsher reed stops. The last and upper manual belongs to the solo organ, which also answers for the echo organ, containing 11 stops, and among them the famous vox humana, the qualities of which have not yet been publicly tested. The pedals are the only remaining key-board, and in connection with them are 20 distinct stops, 15 loud and the rest soft, some of the former being monster reeds and a close imitation of orchestral instruments. We have then a total of 89 speaking stops, which may all be combined, and a grand total of 5474 pipes. The largest of these pipes measure thirty-two feet in length, and are sufficiently capacious in diameter to allow men to crawl through them, while the finest tubes" are too small for a baby's whistle." The breath to these pipes, "to be poured forth in music," is furnished by twelve pairs of bellows, moved by water-power derived from the Cochituate reservoirs.

But this great instrument does not differ from other organs merely in size and wonderful variety of stops, but it excels them in almost every detail which can be mentioned. The principal diapasons are made of the purest English tin which is consistent with stability, and the pipes in the swell organ, although they are always hidden from view, are finished with the most scrupulous nicety. The dip of the keys of ordinary organs is three-eighths, or at the most three-eighths

and a sixteenth of an inch, while the keys of this organ dip no less than five-eighths of an inch, presenting a considerable obstable to players unused to such great depth. But the difficulties which would arise from such a vast amount of mechanism connecting with the keys, asking of an organist's finger the strength of a blacksmith's arm, are overcome by a delicate pneumatic action, which is called too easy rather than otherwise. The arrangement of the stops is controlled to a great extent by the feet, there being twelve separate pedals for this purpose, so that the most beautiful and changeful effects can be made without removing either hand from the key-board. There is also a pedal by which all the stops of the organ may be gradually, one by one or instantaneously, drawn on or shut off, thus producing the most magnificent crescendo and diminuendo, as well as explosive effects. Thus a tone which is scarcely heard at first can be augmented by degrees until it makes the air quiver with its thunders, and then slowly sink again to hushed repose; or the crash can come without warning and with almost deafening power, and as suddenly sink into music of which the listener can catch but the slightest murmurs. The value of such

immense power under perfect control will be easily appreciated.

This great instrument, enclosed in a case of black walnut covered with carved statues, busts, faces and figures in bold relief, is placed upon a low platform, the outlines of which are in accordance with its Its whole height is about sixty feet, its breadth forty-eight feet, and its average depth twenty-four feet.

own.

MANUFACTURE OF BOOTS AND SHOES BY MACHINERY.

The old system of making boots and shoes entirely by hand labor is rapidly yielding to the march of improvement, and will soon, to all арpearances, be numbered with the relics of the past. This change in the character of the manufacture of a great staple industrial product, although slowly progressing for the last eight or ten years in the United States under the spur of competition, has been rapidly consummated within the last two years under the influences growing out of the present civil war; hand labor having proved entirely inadequate to supply the immense demand for boots and shoes required by government for its armies. Machines, therefore, have been invented, and are now in use, executing the different operations necessary to the manufacture of such articles, and with a rapidity and accuracy of action which far excel the efforts of hand labor.

The following interesting account of a manufactory in New York city, in which boots and shoes are made upon an extensive scale by machinery, we derive from a recent number of the Scientific American:

Three large apartments are occupied by the operatives, mechanism, and goods. The skins for the uppers are first spread out, examined, and selected according to the purposes for which they are required. Different cutters then cut out the respective parts according to the size and form required, and these are all arranged and classified. After this these separate parts are given out in lots to be sewed by machines, and those uppers which are intended for boots are crimped, and the whole made ready for receiving the soles. The more heavy operations of punching, sewing, pegging the soles and finishing the articles, are