An attempt to prove the motion of the earth from observations made by Robert Hooke ...

READER,

I Have formerly in the Preface of my Micrographia given the World an account of the founding a Phy∣sico-Mechanical Lecture in the Year 1665, by Sir John Cutler, for the promoting the History of Na∣ture and of Art. In prosecution thereof, I have collected many Observations both of the one and the other kind, and from time to time (as obliged) I have acquainted the Royal Society at their Publick Meetings, both at Gresham Col∣ledge and Arundel House therewith, by Discourses and Lectures thereupon.

Now in order to the further promoting the End and De∣sign of this Lecture, I have complyed, with the desire of several of my Friends (though otherwise not thereunto obli∣ged) to commit divers of those Discourses to the Publick, though of themselves for the most part incompleat, and Es∣sayes or Attempts only upon several Subjects which have no dependencie or coherencie one with another. In the do∣ing hereof, I design to avoid any kind of Method or Order that may require Apologies, Prefaces, or needless Repetitions of what is already known, or might have been said upon that Occasion, or may necessitate me to follow this or that Subject, that doth not some way or other offer it self as it were, and

prompt me to the consideration thereof. But because they may possibly admit of some better order hereafter, I design to print them all of the same Volume, that so they may be, when ranged, either stitched or bound together, and may, as occasion requires, be referred to under the Title of their Num∣ber and Page. This way I chuse as the best for promoting the Design of this Lecture; for as there is scarce one Subject of millions that may be pitched upon, but to write an exact and compleat History thereof, would require the whole time and attention of a mans life, and some thousands of Inven∣tions and Observations to accomplish it: So on the other side no man is able to say that he will compleat this or that In∣quiry, whatever it be, (The greatest part of Invention be∣ing but a luckey hitt of chance, for the most part not in our own power, and like the wind, the Spirit of Invention blow∣eth where and when it listeth, and we scarce know whence it came, or whether 'tis gone.) 'Twill be much better there∣fore to imbrace the influences of Providence, and to be dili∣gent in the inquiry of every thing we meet with. For we shall quickly find that the number of considerable Observa∣tions and Inventions this way collected, will a hundred fold out-strip those that are found by Design. No man but hath some luckey hitts and useful thoughts on this or that Subject he is conversant about, the regarding and communicating of which, might be a means to other Persons highly to improve them. Whence 'twere much to be wished, that others would take this Method in their Publications, and not torment their Readers with such nauseous Repetitions, and frivolous

Apologies, as Method and Volumes do necessitate them to; But would rather inrich the Store-house of Art and Nature with choice and excellent Seed, freed from the Chaff and Dross that do otherwise bury and corrupt it.

The communicating such happy Thoughts and Occurrences need not much take up a mans time to fit it for the Press; the Relation being so much the better the plainer it is. And matter of Fact being the Kernel Readers generally desire (at least in these Subjects) it will be so much the readier for use if it be freed from the thick and hard shell of Impertinences. This way also is more grateful both to the Writer and the Reader, who proceed with a fresh stomach upon variety, but would be weary and dull'd if necessitated to dwell too long upon one Subject. There are other conveniencies also in this Method of Communication not less considerable then the former, amongst the rest the securing of Inventions to their first Authors, which 'tis hardly possible to do by any o∣ther means; for there are a sort of Persons that make it their business to pump and spy out others Inventions, that they may vend them to Traders of that kind, who think they do inge∣nuously to print them for their own, since they have bought and paid for them. Of this there have lately been some In∣stances, and more may be expected, if this way prevent not.

When things cannot be well explained by words only (which is frequent in Mathematical and Mechanical Dis∣courses) I adde Schemes and delineatious Descriptions of that kind being easier to be made and understood. As near as I can I omit the repeating things already printed,

and indeavour to deliver such as are new and my own▪ being my self best pleased with such usage from other Authors.

I have begun with a Discourse composed and read in Gresham Colledge in the Year 1670. when I designed to have printed it, but was diverted by the advice of some Friends to stay the repeating the Observation, rather then publish it upon the Experience of one Year only. But finding that Sickness hath hitherto hindered me from repeating the Tryals, and that some Years Observations have already been lost by the first delay: I do rather hast it out now, though imperfect, then detain it for a better compleating, hoping it may be at least a Hint to others to prosecute and compleat the Observation, which I much long for.

This first Discourse is upon an Observation of Nature, and may therefore be properly referred to that Head, though it contein also somewhat of the Improvement of Art: The second speedily to follow, will more properly be referrable to Artificial Improvements, though it will contein also ma∣ny Observations of Nature; and I design alwayes to make them follow each other by turns, and as 'twere to interweave them, being apart but like the Warp or Woof before contex∣ture, unfit either to Cloth, or adorn the Body of Philo∣sophy.