CHEMISTRY.
[1.] “Galileo,” găl-i-leeˈo. (1564-1642.) An illustrious astronomer, mathematician and philosopher, the creator of experimental science. He made a number of important discoveries in the science of astronomy, among which were Jupiter’s satellites, Saturn’s rings, the sun’s spots, and the starry nature of the milky way. He was a strong advocate of the Copernican system—which represents the sun to be at rest in the center and the earth and other planets to move round it—and for this was twice persecuted by the Inquisition. On both occasions he was publicly compelled to abjure the system, but the last time he is said to have stamped his foot while muttering to himself, “but nevertheless it does move.” The later years of his life were spent in his country house near Florence.
[2.] “Torricelli,” tor-ri-celˈli. (1608-1647.) A celebrated Italian mathematician and philosopher. He made himself renowned for all time by his interpretation of the fact that water will rise in a suction pump to a height of thirty-two feet, which, up to his time, had been explained on the ground that “nature abhors a vacuum;” above that limit the law was modified. Torricelli employed mercury to perform this experiment, and soon found the clue to the mystery. He discovered that the column of fluid was sustained by the pressure of the atmosphere on the open surface of the fluid.
[3.] “Blaise Pascal.” (1623-1662) A distinguished French philosopher and scholar. In his sixteenth year he produced a treaty on conic sections; in his nineteenth year he invented a calculating machine. Turning his attention to the theory of fluids which Torricelli had advanced, he wrote two essays which established his reputation as an experimental physicist. He was the author of the magnificent but unfinished “Pensées.” He was of a deeply religious turn, and before his death was entirely given up to prayer and practices of mortification, among which may be mentioned that of wearing an iron girdle studded with sharp points which he forced into his flesh whenever he felt himself assailed by sinful thoughts. “Puy de Dome,” pwī deh dōm.
[4.] “Tarpeia,” tar-peˈya. The daughter of Tarpeius, the governor of the citadel of Rome. She promised to open the gates of the city to the Sabines if they would give her what they carried on their left hands, meaning their gold bracelets. The king consented, and as he entered the gates, to punish her perfidy he threw not only his bracelet, but his shield upon her. His soldiers followed his example, and she was crushed to death. She was buried in the capitol, which from her has been called the Tarpeian Rock.
[5.] “Haliotis,” hal-i-ōˈtis. A genus of gasteropods with a shell resembling the human ear. The gasteropods are a class of univalve mollusks, like the snail.
[6.] “Skate.” A kind of shark. A name given to several species of fish having a rhomboidal body.
[7.] “Magdeburg Hemispheres.” They are two hollow hemispheres generally made of brass or copper, with edges accurately fitted to each other, and one of them provided with a stop cock. When the edges are pressed tightly together and the globe thus formed is exhausted of air through the cock, the hemispheres are held together with such force that it is with great difficulty they can be pulled apart.
[8.] “Otto von Güricke,” fon gāˈrik-eh. (1602-1686.) A celebrated German physicist. He invented the air-pump and made the famous experiment with the Magdeburg hemispheres.
[9.] “Tower of Pisa.” The round marble belfry called “The Leaning Tower” because it deviates about fourteen feet from the perpendicular. It is 180 feet high, and consists of seven stories divided by rows of columns, and surmounted by a flat roof and an open gallery commanding a splendid view of the surrounding country. It was built in the twelfth century by a German architect, Wilhelm of Innsbruck.
[10.] “Mariotte,” Mä-ri-ŏtˈ. A French philosopher of the seventeenth century. He possessed an extraordinary power of drawing conclusions from experiment. He made a thorough investigation of the subject of the conduction of water, and calculated the strength necessary for pipes under different circumstances.
[11.] “Air-gun.” An instrument resembling a musket. By means of a condenser the air is forced into a metallic globe which is attached to the musket nearly opposite the trigger.
[12.] “Torricellian Vacuum.” To produce this vacuum a small quantity of pure mercury is placed in the tube and boiled for some time. It is then allowed to cool and a further quantity, previously warmed, added, which is boiled, and so on until the tube is quite full; in this manner the moisture and the air which adhere to the sides of the tube pass off with the mercurial vapor.
[13.] “Mont-golˈfi-er.” There were two brothers of this name, Etienne and Joseph, distinguished as the inventors of the first kind of balloons. They were both received as members of the French Academy. They lived in the latter part of the eighteenth century.
[14.] “Pneumatic Dispatch.” The packages are placed on easily rolling carriages which are nicely fitted within tubes. The force necessary to move them is produced by the alternate compression and expansion of air in large reservoirs. This compression and expansion is caused by forcing the water into, and then allowing it to run out of a connecting reservoir, the action being changed by a system of cocks.
[15.] “Gay-Lussac.” (1778-1850.) A Frenchman, one of the most distinguished chemists and physicists of modern times. In 1804 he made a balloon ascension of 23,000 feet, and Humboldt examined with him the air brought down from that height, for the purpose of discovering the intensity of the magnetic force. In 1839 Gay-Lussac was created a peer of France.
[16.] “Lockyer.” (1836-⸺.) An English astronomer. He invented a method of observing the red flames of the sun without being obliged to wait for an eclipse. In 1870 and 1871 he was sent to Sicily by the English government, as the chief of the eclipse expedition.