One of the cleverest inventions ever passed on by the patent office is the machine for sticking common pins in the papers in which they are sold. The contrivance brings up the pins in rows, draws the paper into position, crimps it into two lines, then, at a single push, passes the pins through the paper and sets them in position. The machine almost seems to think as it works, and to examine the paper to see if it is properly folded before pushing the pins into place.

The steam engine in its present form was the invention of James Watt (1768), whose great improvement consisted in performing condensation in a separate vessel from the cylinder, and in producing both the up and down stroke of the piston by steam. The compound engine, in which the steam receives its expansion is a second and larger cylinder, was the invention of Jonathan Hornblower (1781). The marine engine of Elder (1854) is an adaptation of Hornblower's compound engine.

The Eiffel Tower is a colossal iron structure erected by Gustave Eiffel, a French engineer, on the Champs de Mars. It was completed March 31, 1889. It contains three stories, reached by a series of elevators or lifts, and the platform at the summit is 985 feet above the ground. About seventeen hundred tons of iron were employed in its construction; the cost was about $1,000,000. The London Great Tower now (1893) in process of construction will exceed the Eiffel Tower in height by 200 feet and is to be of polished steel.

. The largest and grandest temple of worship in the world is St. Peter's Cathedral at Rome. It stands on the site of Nero's circus, in the northwest part of the city, and is built in form of a Latin cross. The total length of the interior is 6121/2 English feet; transept, 4461/2; height of nave, 1521/2 feet; diameter of cupola, 193 feet; height of dome from pavement to top of cross, 448 feet. The great bell alone without the hammer or clapper weighs 18,600 pounds, or over nine and one-fourth tons. The foundation was laid in 1450 A. D. Forty-three Popes lived and died during the time the work was in progress. It was dedicated in the year 1626, but not entirely finished until the year 1880. The cost, in round numbers, is set down at $70,000,000.

In engineering the caisson is a chest used in "laying" the foundations of the piers of bridges, quays and like structures, in deep and rapid rivers. It consists of a very strong platform of timber or metal plates, to which the sides are attached. The site of the pier being leveled by dredging or otherwise, the caisson is brought over the spot, and moored in the proper position. Two or three of the lower courses of masonry are then built upon the platform of the caisson, and the water is slowly admitted by a sluice, in order to cause the caisson to settle into its place.

The annual manufacture of looking glass in Europe is something like eighteen hundred and fifty thousand square yards. In the mirrors of today the light is reflected by a layer of silver or an amalgam of tin, but a proportion of light is lost in the process of reflection, and the image is less luminous than the original. The value of a looking glass is estimated by the thickness of the glass, because the thicker they are the stronger they must be; but, speaking scientifically, thick glasses are defective, because the outlines of the image reflected are less clearly defined.

The largest ship ever built, the Great Eastern, recently broken to pieces and sold to junk dealers, was designed and constructed by Scott Russell at Millwall on the Thames. Work on the giant vessel was commenced in May, 1854. She was successfully launched January 13, 1858. The launching alone occupied the time from November 3, 1857, until the date above given. Her total length was six hundred and ninety-two feet; breadth, eighty-three feet; total weight when launched, twelve thousand tons. Her first trip of any consequence was made to New York in 1859-60.

The problem of silent machinery has been brought a step nearer solution by the introduction in Austria of cog-wheels made of pressed rawhide, which work in conjunction with wheels of cast iron, steel and other metals. The wheels possess great strength. They do not require lubricating, and are, therefore, clean in operation. They substantially reduce the vibration of the machinery in which they are used. They can be had ready-made or in the form of rawhide disks for shaping by the purchaser. They are supported by a wooden framework, and after being cut the wheel is covered with a shellac solution.

As a process of mining and engineering Blasting is the method of loosening or shattering masses of solid fracturable matter by means of explosive compounds. It is an operation of fundamental importance for, without the agency of powerful explosives, many of the greatest undertakings of modern times would have been practically impossible. The greatest blast ever exploded was in the removal of Flood Rock at Hell Gate, in the East River, New York, when 80,166 cubic yards of rock were tunneled out and 270,717 cubic yards were blasted. The resistance offered equalled 500,000 tons of rock and 200,000 tons of water.

Solomon's Temple was dedicated in the year 1005 b. c. It was eighty cubits in length, by forty cubits in width (cubic = eighteen in.) and thirty cubits high, with a porch one hundred and twenty cubits in height. The Holy of Holies was a cube of twenty cubits each way. Two pillars of brass, eighteen cubits high and twelve cubits in circumference, named respectively Joachim and Boaz, were set up in the porch of the temple, and by some critics have been considered obelisks. Three tiers of small chambers were ranged externally to the walls of the Temple on three sides of the building, and were used for the accommodation of the priesthood.

One of the most famous roads in the world is the "Appian Way," or "The Queen of Roads." It was built by Appius Claudius Caecus while he was censor, 313 B. C. It is the oldest and most celebrated of all the Roman roads, and with its branches connected Rome with all parts of southern Italy. It had an admirable substructure or foundation, from which all the loose soil had been carefully removed. Above this were various strata cemented with lime; and lastly came the pavement, consisting of large hard hexagonal blocks of stone, composed principally of basaltic lava, and joined together with great nicety, so as to appear one smooth mass.