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CHAPTER THIRD.

“MAY I ENCOURAGE YOU, DEAR SIR, NOT TO GROW WEARY IN YOUR MIND, NOTWITHSTANDING THE INFINITE CORRUP. TION YOU MEET IN THE WAYES OF MEN TO STOP YOUR COURSE, BUT TO CONTINUE, AS HITHERTO, TO CAST YOUR BREAD UPON MANY WATERS, FOR ASSUREDLY OF THIS YOU WILL REAP AN ABUNDANT HARVEST IN DUE TIME IF YOU FAINT NOT."-Anon.

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Tue year previous to that in which Sir Samuel Morland exhibited his experiments at St. Germaids, Dr. Denys Papin, an ingenious Frenchman, had ina vented a mode of softening bones by enclosing them in a boiler, constructed to generate steam of a high temperature. By this contrivance he said he extracted “ marrowy nourishing juices from bones, that the most thrifte housewife declared had been abandoned as but poore prey by Je hungry dogs," and beef, “ even the oldest and hardest cow-beef," and other meats, whose horny and shrivelled fibres baffled the skill of the most experienced cooks to prepare for mastication, with common boilers, when “done” in his digester, came forth tender, succulent, and pulpy; in fact, so extraordinary was the effect of this "highpressure steam” process, that the coarsest bones and most obdurate gristle glided gently into the stomach, in the attractive shapes of savoury soups and glutinous jellies ;* and there is little doubt

*«I took beef bones that had never been boiled, but kept dry a long time, and of the hardest part of the leg; these being put into a little glass pot, with water, I included in the engine,

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but that, at one time, Papin was so proud of the power of the new utensil that he had put into the hands of the coquus, that flesh was considered by him to be little better than an excrescence with which nature had concealed and encumbered the virtues of bone and cartilage.

The digesting process being found accompanied with some degree of danger, in the account of his "engine,” which he printed in 1681, when he resided at London, to guard against the fatal effects which would follow the hursting of the boiler, he added a contrivance, which is now well known by the name of the safety valve, an opening made in the cover or roof of the boiler and closed by a lever, pressing a movable weight on the orifice.

“ You must have a little pipe open at both ends, as e, this being soldered to a hole in the cover, a, is to be stopt at the top with a little valve exactly ground to it, and fitted also with a paper between, this must be kept down with an iron rod, one end of which must be put into an iron staple, r, fastened to the bars, and the other end kept down by a weight, o, to be hung upon it nearer or further from the valve, according as you would keep it less or more strongly down upon the end of the pipe to resist the less or greater pressure from within, much after the manner as a weight is hung upon an ordinary Roman balance or steelyard. To prevent the drying of the paper of this valve, a little pipe is tied round having prest the fire until the drop of water would dry away in 8 seconds, or 10 pressures, I found very good jelly in my pot, without taste or colour, like hartshorn jelly; and having seasoned it with sugar and juice of lemon, I did eat it with as much pleasure, and found it a stomachick, as if it had been jelly of hartshorn." New Digester for Softening Bones,

p. 22.

exact."*

SAFETY VALYE.

85 about with hemp and thrust down into the pipe, so that one end reacheth pretty far into the water in the engine, whence it comes to pass, that if some of the said water be lost, the inward pressure will, nevertheless, drive up water through the pipe, e, against the valve and make it more

The valve-pipe must be but slender, that it may be kept shut by a little weight, and his pipe was twofifths of an inch in diameter; the weight at the end of the rod was a pound, placed twelve inches from the valve, and that was one inch from its fulcrum ; and, therefore, when one pound weight was hanging at the end of the lever, and water gets out of the valve, the inward pressure is about eight times stronger than the ordinary pressure; and by increasing or lessening the weight, or by removing it from one place to another, one may always know near enough how strong the inward pressure is.” This lever being merely inserted in a hole made in a projecting rim, it was with difficulty kept in its proper position, and the orifice of the pipe was by this means often unclosed,

* P. 6, ibid.

“Having found some difference, both for the quantity, and for the readiness in drawing jellies from several bodies, I believe there might be found a difference in several other proper. ties of them; and seeing our bodies are but congealed liquors, it is likely that if people would go on with this trial, and draw jellies from several parts of the same animal, and from several animals of the same kind, but of different ages, and from several kinds of animals that live a great deal longer one than another, as from hares and rabbits; and then if they would compare all the several properties of these jellies with one another, it is likely, I say, that it would be a great help towards making a better theory than hitherto we have about the causes of the lastingness of our life, and such a theory would, it may be, prove of more consequence than many people are apt to believe.” P. 28, ibid. Papin practised with success as a physician,

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