case. We have certain indications that an increased intensity of light is not of any advantage, but rather the contrary, for the production of daguerreotypes; the luminous rays appearing to act as balancing powers against the chemical rays. Now, this being the case, we know of no physical cause by which the superiority can be explained, and we are quite disposed to be sufficiently honest to admit that the mode of manipulation has more to do with the result than any atmospheric influences. However this may be, the character of the daguerreotypes executed in America is very remarkable. There are a fulness of tone, and an artistic modulation of light and shadow which, in England, we do not obtain The striking contrasts of white and black are shown decidedly enough in the British examples exhibited in the gallery-but here are coldness and hardness of outline. Within the shadow of the eagle and the striped banner we find no lights too white and no shadows too dark; they dissolve, as in Nature, one into the other, in the most harmonious and truthful manner-and the result is more perfect pictures."

A CALCULATING MACHINE, by Staffel, a Polish Jew, in the Russian Department, was a very ingenious contrivance, for which a Medal was awarded. It was about 17 inches by 9, and 4 inches high. The upper row contained 13 figures, and is immovable. The seoond and third, containing seven figures each-movable. The words Addition, Subtraction, Multiplication, and Division, are engraved on a semi-circular ring to the right; and underneath is a hand, which must be directed to whichever operation is to be performed. The figures being arranged, a handle is turned-the operation instantly performed. If a question be wrongly stated, the error is instantly detected and announced by the ringing of a small bell.

BALANCES were exhibited, of great perfection—a magnetized one from Falmouth, England, would weigh the ten thousandth part of a grain—and a very superior one from France, which was affected by the slightest breath of air.

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ELECTRIC TELEGRAPH Instruments, in great variety, were shown, each kind in operation. The American printing Telegraph was exhibited by an English party. Bain's Telegraph was awarded a Council Medal-as was Bakewell's copying Telegraph-and the same was awarded for an instrument from Prussia-and Prize Medals to several other exhibitors.

A Prize Medal was awarded to Mr. WARD, an English exhibitor, for closed cases, by which plants may be grown in any locality, even in crowded cities, or conveyed from one country to another, with complete success. The use of the cases was suggested to the inventor in 1829. Wishing to obtain a perfect specimen of a sphinx (while residing in London) he had buried its chrysalis in some moist mold in a bottle covered with a lid. Two or three days before the insect assumed its perfect form, a seedling fern and a grass made their appearance on the surface of the mold. In this condition all their wants were supplied. They had sufficient light-whilst the lid, at the same time that it excluded the noxious soot, prevented the escape of the moisture. The law which enforces the diffusion of gases secured a constant circulation of the air, and its quiescent state, enabled the plants to bear variations of temperature which, in open exposure would have proved injurious; various experiments carried on with a great variety of plants, established the conclusion that all plants, whose natural conditions can be fulfilled, can be grown in those cases, in any locality, even in the center of the most crowded cities, or conveyed from one country to another, with complete success.

Mr. Fortune, who was sent out to China by the Horticultural Society of London, put 250 plants in these cases, and landed 215 · in good condition-while in the old plan of carrying plants, it is stated that only one plant in a thousand survived the voyage from China to England. The same pure and moistened atmosphere which favored the growth of the most delicate plants in the heart of the most crowded city, would be of incalculable advantage in numerous diseases.

ATMOSPHERIC RECORDER, by Dollond, in the English department. This was a self-registering instrument, which registered on paper the varying processes of the atmosphere, the changes of the temperature of air and evaporation, and those of the electrical states of the atmosphere, the fall of rain, the amount of water evaporated from a surface of water and the force and direction of the wind. It is a very ingenious, as well as useful instrument— particularly in meteorological investigations—noting every change, however minute, and registering those at night as well as those happening during the day. It received a Council Medal.

COTTON'S SOVEREIGN WEIGHING MACHINE.-A machine which I saw in use at the Bank of England, weighing sovereigns with great rapidity and perfect accuracy, was represented in the Exhibition. It separates with unerring accuracy coins of standard weight, from those that have not that weight. A pile of coins being placed in a tube-the lowest is pushed out by a lever on the end of a beam, which, if the coin is of full weight, is depressed through a small space, but if it be too light, the beam remains stationary. A small piece of steel now advances from one side, on a level with the position that the heavy coin assumes, and immediately afterwards another advances from the opposite side on a level with the position of the light coin. If the coin is full weight the first advancing piece pushes it into a receptacle, and the second has no effect; if, on the contrary, the coin is light, the first passes under it, and the second strikes it into another receptacle. This is operated by steam power, and there are a dozen at the bank frequently all in operation at the same time, and the rapidity and certainty, with which they work is truly wonderful. This was introduced late into the exhibition, but I believe received a prize medal from the Jury.

MUSICAL INSTRUMENTS were also in this class, submitted to a sub-jury. In this division there was a great variety of instruments exhibited. Organs of immense power-one by Willis, of London, which is said to weigh 30 tons, with 5,000 pipes-a great variety of piano fortes, &c. From the United States there were a number of

pianos exhibited, and although in the early part of the Exhibition they were slightly noticed by the press, every one of them received an award of a Medal or Honorable Mention. Chickering, Meyer, Nunns &Clark, received medals. Gilbert & Co., Heers & Pirsson, Honorable Mention; and Wood of Virginia, a money award of £50, for his Piano Violin, which attracted attention from its ingenuity, and was in constant requisition to satisfy the eager curiosity of visitors. Goodyear, of the United States, received Honorable Mention for an India Rubber flute.

HOROLOGICAL, Clocks and Watches. The number in this sub-division was immense, and of every conceivable size and variety. France and Switzerland exhibited very largely, and received a large portion of the prizes. Dent, of London, celebrated for his superior work, received a Council Medal for a Turret clock. In the French department, were a very great number of very elegantly finished clocks, of almost every imaginable variety of form. In the Austrian department, was exhibited a clock for which is claimed the realization of perpetual motion-continuing to move until its materials are worn out; the power which winds it up, being the varying pressure of the atmosphere acting on quicksilver, which turns a wheel and accomplishes the work. The American exhibition of clocks was of considerable variety, and unusually cheap-these found more favor with purchasers than they did with the jury. Geneva, so long celebrated for miniature watches, exhibited the smallest watch ever made. It was inserted in the top of a gold pencil case, was of an inch in diameter, which on its dial gave the seconds, minutes, hours and days of the month. A magnifying glass was by the side of it, to enable all to see its perfection of finish, which many, by the naked eye, could not clearly distinguish. In connection with this, was exhibited a piece of tiny mechanism-very ingenious—a small pillar of a few inches in height, the top of which opens at the touch of a spring, and a little bird, most perfect in its construction, in the very motions of life, sings a brief song and then retires. Price $80. There were many curiosities in this division, that attracted much notice, several of them constructed by persons not connected with the trade.

There was one clock which gave the time of the day in every part of the world, which occupied 31 years in the manufacture, requires to be regulated once in 130 years. A clock made by a tailor, gave the days and months, the motions of the sun and moon, the state of the tide in various countries, and runs for 12 months; and a musical clock, made by a blacksmith, played a tune every three hours.

SURGICAL INSTRUMENTS.-In this sub-division, there was an exhibition of the improvement made in this department-no Council Medals awarded, and not a very large number of Prize Medals. Palmer's artificial leg, from this country, received a medal, to which it was most justly entitled. Among the great number of preparations there was none that compared with this-and I was informed that the Marquis of Anglesea, who left one of his limbs at the battle of Waterloo-had Mr. Palmer before him, with his leg, and, in the midst of a collection not numerous enough to supply a large army, yet very extensive-this was pronounced superior to all. I did not learn whether one was prepared for the Marquis-but probably he has, ere this, tried its quality. In the French Department, the collection of superior instruments were of great variety and finished most perfectly. The anatomical models from France were very perfect, and are now generally introduced as aids to the study of Anatomy. These comprised not only the human figure but those of domestic animals. Various instruments for aiding the hearing, which may be worn without being noticed, were shown.

In the English department, one exhibitor presented a complete cabinet of surgical instruments, containing all that was necessary for general operations in surgery, with the latest improvements. The collection was very admirably executed, and was, in all respects, most perfect, and was awarded a Prize Medal, to which it was certainly entitled, from its great excellence. Dental instruments were exhibited by several exhibitors from this State, of very high finish and equal to any shown.