cluded, that the Sun's Parallax might be duly determined by fuch Obfervations, if Mercury being nearer the Earth, had a greater Parallax, when feen from the Sun; for, this Difference of Parallaxes is fo very inconfidera ble, as to be always lefs than the Sun's Parallax, which is fought; confequently, tho' Mercury is to be frequently feen within the Sun's Difk; he will scarcely be fit for the prefent PurVIII. Therepofe. ‡ (To be continued.) T S E ‡ The Sun's Parallax having been stated at 12" the Parallax of Mercury is eafily known by the known Ratio of its Distance from the Sun and Earth, but this will be best explained by a Diagram; therefore let S be the Sun, M Mercury, and E the Earth, whofe Semi-diameter is É T, draw the Lines SE, ST, and MT, then is the Angle TSE 12" the Sun's Parallax, and E M T is the Parallax of Mercury, and the Dif Now as thefe Parallaxes, and their ference of thofe Parallaxes is the Angle MTS. Difference, are proportional to the Lines MT, ST, and S M, which are in a given Ratio to each other, they will also have a conftant Proportion among themselves, and therefore when any one of them is known, or fuppofed to be known, the others will be known according to that Hypothefis. For Example, if the Solar Parallax TS E be 12", then it will be MT: ST(or ME :SE):: 6129: 10000 :: 12": 20" TME, the Parallax of Mercury, nearly; then the Difference is 7 for the Angle M TS, on the above Suppofition. Now this Difference of Parallaxes is lefs than the Sun's by more than 4"; and fince the Parallax of the Sun is to be found by the Difference of the Parallaxes from Obfervation; the Planet Mercury will not be fo proper for this Purpose as Venus, where the Difference of Parallaxes will be fo much more confiderable, MATHEMATICAL QUESTIONS Answered. IRST correcting the Prefs by putting x2 x2 instead of x2 y2, then by making y to FIRST x flow we get y= and by making z to flow we have ≈ = xx then by fub xx x4 ftituting their Values we have a4 - x4 X X which fluxed, and reduced pro 4 perly, gives x = 17,6 y=35,2 and x 12,201. QER. Mr. Chapman's own Numbers are different from the above, for be makes x=352,04464, and y = 176,02232, and z = 248,933. LE Question 267, anfwered by the Propofer. ET 36 Chains, then its first or leaft Side is a, then let e 3, i=7, and 10, from which the four Sides -i. A will be thus found; a = B Question 268, anfwered by the Proposer Mr. Barak Longmate; N the annexed Scheme let A be the Sloop, B the Ship, A B 2,5, BC the Sloop's Courfe, CD the Race of the Current in Proportion: BC as 2 to 6, and DCB 45. Now as the Current fets equally to them both, it caufes no Alteration in the Courfe which the Sloop must steer, which is plain must be A C, therefore VAB2+B CAC6 Miles the Sloop fails, to overtake the Ship in the leaft Time poffible; and to find the Course, say as A C: Radius:: BC to Sine 4 CAB B A C 67° 23', its Complement 22o, 37′ —4 C, whence the Course was E. N. E. 7'E. To find the Bearing and Distance of D from B, fay as BC+DC: BC-DC::/ 4D+ 4 B 4D-4B :t .. 4B 17° 8', whence the Courfe made good by the 2 2 Sloop was Eaft by North, 5° 53' East; and as Sine ▲ B : DC; : Sine ▲ C:BD= 4,8 Miles diftance from the Ship at B, and the Chafe will last one Hour. N. B. This Queftion was proposed as Mr. Carter's by mistake. Mr. Charles Green also anjqvered this Queftion in Numbers, nearly agreeing with the Propofer's. IN Question 269, anfwered by Mr. George Redaway. N the Triangle ABC, we have given all the Angles; and G B GHC New QUESTIONS to be answered. Question 276. By Mr. James Garden. IVEN the folid Content of the Fruf tum of a Cone 35,4520833 Feet, the flant Height 81,394103 Inches, and the Difference of Diameters = 30 Inches, to find the Diameters ? A Calculation of the Lunar Eclipse, by Mr. T. Smith, at Lamberhurst. Apparent Time 1761, Middle of End of Beginning Beginning Eclipfe. Tot.Dark. End of h/ h 1 } Duration of Total Dark, 1 34 30 3 23 24 An Eclipfe of the Moon, May 29, 1760, by Mr. B. Talbot. In thefe Computations I have added as many Seconds, as the Moon's Parallax contained Minutes; alfo it may be obferved, as the Earth is not an exa& Sphere, its Shadow cannot be fo, but Elliptical, and may caufe a Variation in the Duration of Eclifpes. Therefore the Middle (if it can be observed or obtained from fome other Obfervations made during an Eclipfe) is most proper to compare with Computations, in order to prove the Tables in Longitude. It's therefore hoped, the Middle of the foregoing Computa tions will agree very nearly with correct Observations. I am your's &c. Newport, Shropshire, March 10, 1760. Benj. Talbot, Teacher of Mathematics. BAROMETRICAL and THERMOMETRICAL OB SERVATIONS made at Hull, by B. Waddington, in Mard N. B. In answer to a Query of an ingenious Correfpondent, whether a Man who walks quite round the Globe of the Earth (Jupposed to be a perfe Sphere) walks moft up Hill or down? We anfwer, That fuch a Perfon can neither walk up Hill nor down, for no one goes up Hill, unless he goes farther from the Center of the Earth, nor down Hill, unless he approaches nearer to the faid Center; but the Perfon in Queftion, is always at an equal Distance from the Earth's Center, therefore, &c. A fmile, the thought, would drefs her looks too gay, A frown, might feem too fad, and blast the day. But while nor this, nor that, her will could bow, She walk'd and look'd-and charm'd and knew not how. Our hands at length th unchanging fiat bound, And our glad fouls fprung out to greet the found. Which only death's keen weapon can divide, moon? If we fo fhort a space our blifs enjoy, Women, thus us'd, like bubbles blown with air, Owe to their outward charms a fun-gilt glare: Leaft more, faid I, thou should't profane I'll feal thy dang 'rous lips with this clofe kifs; But learn from me to speak on this lov'd theme. one. Union of hearts, not hands, does marriage make, *Tis fympathy of mind keeps love awake: Our growing days increase of joys fhall know, And thick-fown comforts leave no room for woe. Thou the foft fwelling vine, shall fruitful laft, my bofom play. Thou for protection, fhait on me depend, Thou shalt first partner in my pleasures be, If all life's race were wedding-days like mine! Ell me, bright nymphs! why with fuch Thofe fleeting charms you labour to repair? While all undreft, unpolish'd, unrefin'd, Which dart more light than earth can boaft Think then, moft fair! if 'tis not low and To fee angelic beauteous fingers chafe And to whofe motion empires ftand confin'd: The mortal stamps, with immortality: Convey'd without a blush from pole to pole. As ever, therefore, you defire in fate, What's wealth and riches, but a gilded toy, What's fame and honour, but an empty blaft, What's love and beauty, but a fleeting joy, |