A new discovery for finding the longitude

by William Hobbs

Which 9 deg. 15.5. min. being added to, or taken from the Longitude of the Place, where the said Movement was first set in Motion, gives the Longitude you are come into, as effectually as the Latitude is obtained by Observation, as was at first proposed. So that it is evident, that if any defect should be found in practice, it must proceed from the Vicissitude of the Air; and not from any Deficiency in this Discovery, or from the Cannons relating thereunto.

And that we may Answer all Objections, which may arise, on Account of the said Vicissitude of the Air, Motion of the Ship, Foulness of the Movement, &c. as well as render this Discovery more intelligible, we will descend to speak thereof more particularly: And,

In the first place, let Five or Six (or what Number you please) of these Movements be made; and after they have gone for a Month or two, (or if designed for the Sea, ’till within two or three Weeks of your Sailing) then take them asunder, and set them going by the Meridian Line, as before directed. And having entred down in the Book, herein after mentioned, the Day of the Month, when set going; how long it is making one Revolution; and what Number is produced, in just Ten Days Motion, (all which must be done, before you Sail in every Voyage;) Let them be carry’d to Sea, into any Latitude, (suppose 50 Deg. or Newfoundland) and at their Return bring them again to the said Meridian Line, and thereby (with the help of the Number of Days from their being first set in Motion) find the two first Proportional Numbers, as before directed: Which done, enter them in a Book, peculiar to each Movement, (the Form whereof followeth) together with the Latitude, and Season of the Year in which the Voyage was made. Then will they all be fitted for a Voyage to Newfoundland, and Parts adjacent, for any such Season. And so for any other, when Tried and Entred, as now directed.

After which, send them all in a Ship bound to the Latitude of about 37 Deg. (suppose Virginia); and being returned, let the Numbers be found and entred, as aforesaid, with the Latitude and Season; then will any one, or all of them, be fitted for a Voyage, either to Newfoundland or Virginia, or any of those Parts, for any such like Season; and so for any other, when Tried and Entred as aforesaid.

This being done, send them also in a Ship, bound to the Latitude of 13 Deg. (suppose Barbados or Jamaica;) and being returned, find the Numbers, and enter them with the Latitude and Season: So will they all be fitted for these several Latitudes, (viz.) 50 Deg. 37 Deg. and 13 Deg. at such a Season: And by a like Process to the Æquinoctial, and towards the North Pole.

Upon which several Tryals, you will have so many Movements fitted for all the North Hemisphere, both for Hot, Cold and Temperate Seasons. And, by only Counterchanging the Latitudes, for the whole Globe; or at least for the Marine Parts thereof.

And to what is proposed to be Entred, in respect of Latitude and Season, you may also add the Time of its being first set in Motion after Cleansing; which Cleansing must be done only Annually, and as near as may be on the same Day of the Month; which will much facilitate the Inequality arising from its Foulness: By which all Objections will be answer’d, and the Discovery render’d compleat and perfect. Especially if a true Meridian Line be made in every considerable Port in this Kingdom, and elsewhere; for Examining the Movement at your Arrival abroad, and setting it in Motion, before your Departure. But remember, that where you set it going, from thence your Departure must be reckon’d.

And by this Method all the said Vicissitudes that may arise in respect of Latitude or Seasons, Motion of the Ship (which will be near the same in one Voyage, as in another) and Cleanness or Foulness of the Work, will also plainly appear upon Record, (by comparing one Number in the said Book with another) and will be Accounted for, and Æquated, as occasion requires: Namely, by only taking such Numbers from the said Book, to work your Proportion by, as are entred for the Latitude and Season, that you are again Arrived to, or Sailing under: As suppose into 50 Deg. in the Summer Season, then take the Number and Hours answering thereunto; and so, if in Winter, those for the Winter. By which proportionable Numbers, the said Contingencies will be truly and effectually Allowed, and the Difference in Motions justly Æquated, as was before asserted.