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Torricelli .

[Book II.

ascend higher. He then reduced the length of the pipe to 40 feet, withoutany better success. It now occurred to him, that if it really was theatmosphere which supported this column of water in the pipe, then, if heemployed some o ther liquid, the specific gravity of which, compared withthat of water, was knoten, a column of such liquid would be sustained inthe tube, of a length proportioned to its gravity. This beautiful thoughthe soon submitted to the test of experiment, and by a very neat and simpleapparatus.

Quicksilver being 14 times heavier than water, he selected it as themost suitable, since the apparatus would be more manageable; and fromthe small dimensions of the requisite tube, a syringe to exhaust the aircould be dispensed with. He therefore took a glass tube about four feetlong, sealed at one end and open at the other. This he completely filledwith quicksilver, which of course expelled the air; then placing his fingeron the open end, he inverted the tube, and introduced the open end belowthe surface of a quantity of mercury in an open vessel; then moving thetube into a vertical position, he withdrew his finger, when part of themercury descended into the basin, leaving a vaeuum in the upper part ofthe tube, while the rest was supported in it at the height of about 28inches, as he had suspected, being one-fourteenth of the height of theaqueous column. This simple and truly ingenious experiment was fre-quently varied and repeated, but always with the same result, and musthave imparted to Torricelli the most exquisite gratification.®

Accounts of Torricelli ’s experiments were soon spread throughout Eu-rope, and every where caused an unparalleled excitement among philoso-phers. This was natural, for his discovery prostrated the long cherishedhypothesis of nature’s abhorence of a vaeuum; and at the same time, openedunexplored regions to scientific research. It met however with muchOpposition, particularly from the Jesuits ; in many of whom it is said tohave excited a degree of ‘ horror’ similar to that experienced by them onthe publication of Gralileo’s dialogues on the Ptolemaic and CopernicanSystems. They and others resisted the new doctrine with great perse-verance, and even endeavored to reconcile the results of the experimentswith the fuga vacui they so long had cherished. It was ingeniously con-tended that the experiment with quicksilver no more proved that the forcewhich sustained it in the tube was the pressure of the atmosphere, than thecolumn of water did in the first experiment; allowing this,. it proved thatthis force, whatever it was, varied in its effects on different liquids, accord-ing to their specific gravity ; a fact previously unknown, and apparentlyinconsistent with nature’s antipathy to a void, which might be supposed toproduce the same effects on all fluids—to have as great an abhorence tomercury as to water.

Düring the discussion great expectations were entertained by the advo-cates of the new doctrine from Torricelli ; but unfortunately, this philoso-pher died suddenly in the midst of his pursuits and in the very vigor ofmanhood, viz. in his 39th year. This took place in 1647. The subjectwas however too interesting, and too important in its consequences, to belost sight of. He had opened a new path into the fields of Science^ andphilosophers in every part of Europe had rushed into it with too muchardor to be stopped by his decease. Among the most eminent of those

“The apparatus employed in these experiments was not original with Torricelli .The air thermometer of C. Drebble, the famous alehemist, who died in 1634, was of thesame construction, except that the upper end of the inverted tube was swelled into abulb. It is frequently figured in Fludd’s works.