Other writers saw no good reason for depriving the captain of the title of inventor. With reference to the book-burning allegation, the only evidence tending to substantiate it lay in the fact that the book “on a sudden became very scarce, and but few copies of it were afterwards seen, and then only in the libraries of the curious.”[74] It has been remarked, also, that Desaguliers was himself to some extent a rival claimant, several improvements, such as the substitution of jet for the original surface condensation being due to him; and that this fact gave a palpable bias to his testimony on the work of others. In recent years the claims of Savery have been upheld, as against those of the marquis, by a writer who argued, not only that the engine of the marquis had never passed the experimental stage, but that no counter-claim was made by his successors at the time Savery produced his engine and obtained his patent. “Although a patent for ninety-nine years (from 1663 to 1762) was granted the marquis, yet Captain Savery and his successors under his patents which extended for thirty-five years (from 1698 to 1733) compelled every user of Newcomen’s and other steam engines to submit to the most grinding terms and no one attempted to plead that Savery’s patents were invalidated by the Marquis of Worcester’s prior patents.”[75] By the admirers of Papin it has been claimed that it was from him that Savery received his idea. “After having minutely compared Savery’s machine,” says a biographer of Papin, “one arrives at the conviction that _Savery discovered nothing_. He had borrowed from Solomon de Caus the use of steam as a motive force, perfected by the addition of a second chamber; from Papin, the condensation of the steam.... And as for the piston, borrowed ten years later by Newcomen, that was wholly Papin’s.”[76] Suppose it true; even so, his countrymen would always think great credit attaches to Savery for his achievement. His engine, though used extensively for lifting water through small distances, was exceedingly wasteful of fuel, nor could it be used conveniently for pumping out mines or for other purposes in which a large lift was required. The lift or “head” was directly proportional to the steam pressure. Efforts to improve the lift by augmenting the steam pressure resulted in endless accidents and discouragement; the solder of the engine melted when steam of a higher pressure was used, the joints blew open and the chambers burst.