Your kindness in countenancing this invention in its first appearance in the world, gives me hopes the usefulness of it will make it more acceptable to your honourable Society, as they are the most proper judges of what advantage it may be to mankind. And it would be ungrateful in me not to make use of this opportunity to return you my most humble and hearty thanks for the honour and favour you did me in approving my design, and publishing it to the world,[1] which shall be always acknowledged by Your most obliged and most humble Servant, THOMAS SAVERY. [1] Philosoph. Transact. Numb. 252. TO THE GENTLEMEN ADVENTURERS IN THE MINES OF ENGLAND. I am very sensible a great many among you do as yet look on my invention of raising water by the impellent force of fire, a useless sort of a project, that never can answer my designs or pretensions; and that it is altogether impossible that such an engine as this can be wrought under ground, and succeed in the raising of water, and draining your mines, so as to deserve any encouragement from you. I am not very fond of lying under the scandal of a bare projector; and, therefore, present you here with a draught of my machine, and lay before you the uses of it, and leave it to your consideration whether it be worth your while to make use of it or no. I can easily give grains of allowance for your suspicions, because I know very well what miscarriages there have been by people ignorant of what they pretend to. These I know have been so frequent, so fair and promising at first, but so short of performing what they pretended to, that your prudence and discretion will not now suffer you to believe any thing without a demonstration, your appetites to new inventions of this nature having been balked too often; yet, after all, I must beg you not to condemn me, before you have read what I have to say for myself; and let not the failures of others prejudice me, or be placed to my account. I have often lamented the want of understanding the true powers of nature, which misfortune has, of late, put some on making such vast engines and machines, both troublesome and expensive, yet of no manner of use, inasmuch as the old engines, used many ages past, far exceeded them; and I fear, whoever, by the old causes of motion, pretends to improvements within this last century, does betray his knowledge and judgment; for more than an hundred years since, men and horses would raise by engines, then made, as much water as they have ever since done, or I believe ever will, or according to the law of nature ever can do; and though my thoughts have been long employed about water-works, I should never have pretended to any invention of that kind, had I not happily found out this new, but yet a much stronger and cheaper force or cause of motion, than any before made use of. But finding this of rarefaction by fire, the consideration of