CHAPTER III.

PAPIN IN LONDON.-HIS FIRST PNEUMATIC ENGINES.

SHORTLY after arriving in the metropolis of England, Papin addressed himself to the Honourable Mr. Boyle, and in August, 1675, we find him already employed by Mr. Boyle in making a translation of a theological treatise.1 Ere long he was put to a class of work more congenial to his disposition, viz. the prosecution of another series of pneumatical experiments.

Papin had brought to Mr. Boyle a copy of his treatise, on the experiments made by Huyghens and himself at Paris, which greatly interested Mr. Boyle. The opportunity afforded by the presence of Papin, who had moreover a double-barrelled air-pump of his own invention (Fig. 10), decided Mr. Boyle to commence a

2

1 Vie de Papin, par L. de la Saussaye et A. Pean. Vol. I., p. 95. 2 It is sometimes stated that Papin invented the double air-pump while in the employment of Boyle, but the reason given by Boyle for allowing him to use his own pump, viz., because he was more accustomed to it, seems to point to his having used it a good deal before

CH. III.]

PAPIN EMPLOYED BY BOYLE.

27

third series of experiments with the assistance of Papin. These experiments were begun in July, 1676, and continued till February, 1679. Some of the later experiments, Mr. Boyle informs us, about flesh, about fruit, and about boiling of meat, were propounded

FIG. 10.-PAPIN'S DOUBLE AIR-PUMP, ABOUT 1675-6.

This was the first air-pump provided with valves, which were opened and closed by the action of the machine. The operator worked the pump with his feet, placing one in each of the rectangular "stirrups." The barrels, or cylinders, were partially filled with water to render the pistons air-tight.

by Papin for a particular end of his own, somewhat different from the design of the rest of the experiments.1

he came to Boyle. See Birch's Boyle, Vol. IV., pp. 96-97. There is, however, no allusion to a double-pump in the tract published by Papin in 1674. 1 Birch's Boyle, Vol. IV., p. 97.

Soon after the conclusion of his engagement with Mr. Boyle, the first connection of Papin with the Royal Society commenced. At the meeting of the Society held May 22nd, 1679, Mr. Hook, the secretary, "had leave to introduce Mons. Papin, a gentleman who staid in the outer room, with an intention to shew an experiment to the Society which was singular and new." This had reference to his method of cooking in a close vessel at a high temperature by means of an apparatus invented by him and known as "Papin's Digester."

1

On June 19th, we find Papin exhibiting to the Royal Society a new kind of wind-fountain of his own contrivance;" and at the meeting of the Society on July 3rd, Mr. Hook was empowered to employ Papin for the writing of all such letters as should be ordered to the correspondents of the Society, at so much per letter; an arrangement soon afterwards altered for a certain payment of 201. per annum, with lodgings in Gresham College if they could be found.3

This engagement was of very short duration. At the meeting of the Society on December 10th, 1679, "it was ordered that Mons. Papin should be discharged, but that he be allowed for the time till he be discharged and paid accordingly."4

1 Birch's History of the Royal Society, Vol. III., p. 486.

2 Ibid. Vol. III., p. 490.

Ibid. Vol. III., p. 514.

3 Ibid. Vol. III., p. 491.

111.]

HIS DIGESTER.

29

From this time till near the close of the following year nothing is heard of Papin, but it would appear from statements of his own, to be hereafter referred to, that he spent part of the time at least in Paris, living with Huyghens, and assisted in the invention of the gunpowder engine.1 At the meeting of the Royal Society on December 2nd, 1680, we find him again present and exhibiting his "boiling engine" to the Society. At the following meeting (December 8th) his book, entitled A new Digester or Engine for softening bones, &c., was ordered to be printed. He is sometimes stated to have been elected a Fellow of the Royal Society on December 16th, through the influence of Mr. Boyle; but this appears to be incorrect, as in the order of the

1 See post, p. 47.

2 Birch's History of the Royal Society, Vol. IV., p. 60. Papin used a safety-valve on his Digester, and is usually credited with being its inventor; but it appears to have been known at a much earlier date. (See Ewbank's Hydraulics, 15th ed. p. 451.)

The Digester continued to receive Papin's attention from time to time for many years. The early history of this curious machine is not without some amusing incidents. At the time of its invention Papin suggested its use in hospitals to the Government of Charles II., but the court laughed at the Digester and its products. (Denis Papin, par le Baron Ernouf, p. 55.)

Evelyn tells us in his Diary [12th April, 1682] of a supper cooked by the Digester, to which he accompanied some of the Fellows of the Royal Society, who wished, by practical experiment, to make trial for themselves of its culinary value. In concluding his account of the repast he observes-"This philosophical supper caus'd much mirth amongst us, and exceedingly pleas'd all ye company. I sent a glass of ye jelly to my wife, to the reproach of all that the ladies ever made of their best hartshorn."

Council dated December 8th he is described as "Doctor of Physick, and Fellow of this Society."

In the beginning of the year 1681 Papin again left England. At the house of Boyle he had made the acquaintance of Sarotti, the representative of the Venetian senate at the English court. Sarotti was about to establish a philosophical society at Venice, and proposed that Papin should accompany him there to take the post of Curator of Experiments to the society. Papin accepted the offer, and took his departure for Italy accordingly.1 Here, however, he remained only about three years, after which he returned once more to London.

He now renewed his connection with the Royal Society, and on April 2nd, 1684, was appointed temporary Curator at a salary of 301. per annum.2 His principal duty was to bring experiments before every meeting of the Society, a necessity which could not fail to serve as a powerful stimulus to his inventive faculties. Among the numerous notices of the contrivances which he exhibited at the Royal Society's meetings, we shall confine our attention to such only as bear immediately on our subject, which do not begin until rather more than a year after he had obtained the above appointment.

1 Vie de Papin, par L. de la Saussaye et A. Peun, Vol. I, p. 111. 2 Weld's History of the Royal Society, London, 1848, Vol. I., p. 286. Birch's ditto, Vol. IV., p. 277.