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Page:Popular Science Monthly Volume 44.djvu/257

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THE ESSAYS OF JEAN REY.

and we find numerous fragments of earthenware pipes of various forms, but most of the specimens of this sort are merely fragments. A few entire pipes of the same mixture of clay and pounded stone which we have in the jars are in existence. One of these is shown in Fig. 13, Earthenware pipes of the same general form as that seen in Fig. 8 have also been found, and very likely this was the more common shape. The pipe represented in the figure is unusually thick and heavy, and apparently was made for service rather than ornament. It is three inches long, and the diameter at one end is an inch and a half, at the other about an inch. The bore is rapidly contracted, so that it soon becomes quite small. Most of the earthenware pipes of this region are very smooth on the outside, having received a finishing coat of fine clay, but this is without it, though the surface is tolerably smooth.

 

THE ESSAYS OF JEAN REY.
By MM. L. A. HALLOPEAU and ALB. POISSON.

AMONG the men of science of the first half of the seventeenth century the name of Jean Rey, doctor, of Périgord, was long forgotten and is still little known. He was born toward the end of the sixteenth century, at Bugues la Dordogne. Hardly anything is known of his life. He was a doctor of medicine, and devoted himself for several years to researches in chemistry and physics, in co-operation with his elder brother, also named Jean Rey, Sieur de la Perotasse, proprietor of the iron forge at Rochebeaucourt, la Dordogne. He died in 1645, and his days may have been cut short by grief over a disastrous lawsuit.

Jean Rey invented a water thermometer, or thermoscope, and a wind arquebus, and he even thought of applying his thermometer to the uses of medicine. It was certainly one of the first instruments invented to measure differences of temperature. In his description of it he said: "It is nothing but a little round vial with a long, uncorked neck. In using it, I place it in the sun or in the hands of a fever patient, after having filled it, all except the neck, with water. The heat, dilating the water, causes it to rise more or less, according as the heat is great or little."

He wrote one little book of a hundred pages, dedicated to the Count de la Tour d'Auvergne, which was printed in 1630, under the title of Essais de Jean Rey, Doctor of Medicine, on an investigation of the cause of the increase in weight of tin and lead when they are calcined. This work was not understood by the learned men of that period. It was probably not very widely published.