The Life of Dr. Robert Hooke.

This, together with his former performances, made him much respected by the Royal Society. On the fifth of November 1662, "Sir Robert Moray proposed a person that was willing to be entertained as a curator by the Society, offering to furnish them every day when they met with three or four considerable experiments. This proposition was unanimously received, Mr. Hooke being named to be the person. Accordingly, the next day of their meeting, on the twelfth of November, he was unanimously accepted and taken as curator, with the thanks of the Society ordered to Mr. Boyle for dispensing with him for their use, and it was ordered that Mr. Hooke should come and sit among them, and both bring in every day three or four of his own experiments, and take care of such others as should be recommended to him by the Society."

From this time, the Society’s journals give sufficient testimonials of his performances, all of which would be too many to particularize here. Therefore, I shall only touch upon some of the chief ones, such as the experiment of breaking glass bubbles inward. The air contained in them was rarefied by heat during their blowing, and they were hermetically sealed while hot. These bubbles were observed at a certain degree of tension—both when distending them while blowing and in their contracting as they cooled—to yield a smart sound. Several of these would break inwards with a brisk noise upon cooling, though others broke without any noise, upon which the experimenter made several remarks.

Many experiments were made to explain the nature and quality of the air, namely as to its gravitation, its different effects when rarefied, condensed, and in its natural state, and its use regarding the life of animals and the maintenance of a lucid flame, or the dissolution of bodies by fire. A live animal and a lamp being enclosed together in a receiver showed the pabulum vitae original: "pabulum vitae et flammae"; modern: "food of life and flame" and flammae to be much the same. At which time also he tried how long the same air would serve for breathing. This leads me to remember that noble experiment made by him of keeping a dog alive, with its thorax being laid open, by blowing fresh air into its lungs, of which a particular account is given in the History of the Royal Society, page 232, which plainly shows the use of the air and the difference between venous and arterial blood.

He showed what addition of weight is given to fluids by ascending and descending bodies in them. He examined the different specific weight of hot and cold water, with the uses to be made thereof in heating large quantities of water. He studied the difference between ice and water, and the refraction of other fluids, by an instrument described in the preface to his Micrographia.

He conducted experiments and designed a device to show the force and velocity of bodies falling from several heights, as well as weighing bodies at several heights. He used pendulums of two hundred feet long, studied the difference of the barometer at several heights, conducted experiments to improve land carriage, and developed methods of conveying secret and quick intelligence.

He created instruments to measure time exactly, to observe a second minute by the sun or stars, and to try the strength of gunpowder. Among several others, he invented an engine to cut the teeth of watch wheels more exactly than can be done by the most expert hand, an invention now of constant use.