24 THE POPULAR SCIENCE MONTHLY. 



tion of the Marquis of Worcester was revived twenty years later, by 

 Sir Samuel Morland, but in what form is not now known. 



In a memoir, 1 which he wrote upon the subject in 1683, he exhib- 

 ited a degree of familiarity with the properties of steam that could 

 hardly have been expected of any one at that early date. 



In his manuscript, now preserved in the Haarlem Collection of the 

 British Museum, he states the size of the cylinders required in his 

 machine to raise given quantities of water per hour, and gives very 

 exactly the relative volumes of equal weights of water and of steam 

 under atmospheric pressure. 



He tells us that one of his engines, with a cylinder six feet in 

 diameter and twelve feet long, was capable of raising 3,240 pounds 

 of water through a height of six inches, 1,800 times an hour. 



15. From this time forward the minds of many mechanicians were 

 earnestly at work on this problem the raising of water by aid of 

 steam. 



Hitherto, although many ingenious toys, embodying the principles 

 of the steam-engine separately, and sometimes, to a certain extent, 

 collectively, had beeu proposed and even occasionally constructed, 

 the world was only just ready to profit by the labors of inventors in 

 this direction. 



But, at the end of the seventeenth century, English miners were 

 beginning to find the greatest difficulty in clearing their shafts of the 

 vast quantities of water which they were meeting at the considerable 

 depths to which they had penetrated, and it had become a matter of 

 vital importance to them to find a more powerful aid in that work 

 than was then available. 



They were, therefore, by their necessities, stimulated to watch for, 

 and to be prepared promptly to take advantage of, such an invention 

 when it should be offered them. 



16. The experiments of Papin, and the practical application of 

 known principles by Savery, placed the needed apparatus in their 

 hand s. 



When Louis XIV. revoked the Edict of Nantes, by which Henry 

 IV. had guaranteed protection to the Protestants of France, the ter- 

 rible persecutions at once commenced by the papists drove from the 

 kingdom some of its greatest men. 



Among these was Denys Papin, a native of Blois, and a distin- 

 guished philosopher. He studied medicine at Paris, and, when ex- 

 patriated, went to England, where he met the celebrated philosopher 

 Boyle, who introduced him into the Royal Society, of which Papin 

 became a member, and to whose " Transactions " he contributed sev- 

 eral valuable papers. 



He invented, in 1680, the " Digester," in which substances, unaf- 



1 " Elevation des Eaux, par toutes Sortes de Machine, reduite a la Mesure, au Poids 

 et a la Balance." 



