agreeable manner, the rotation of our earth on its axis in the proper direction, from west to east; and if the globe, whilst thus rotating, be gradually carried round the inside of the inclined hoop, the alternate succession and different lengths of days and nights throughout the year will be made evident to sight, as also the varied change of the seasons, Spring, Summer, Autumn, and Winter. Referring to the annexed engraving, the letter A indicates the position of the earth at the vernal equinox, 21st March. The centre of globe being on a level with the candle flame (which represents the sun), will be enlightened from pole to pole, same as the globe is when in the opposite position, thereby causing equal day and night all over the world. The letter B shows the position of the earth at the summer solstice, 21st June. Here it will be observed that the small globe is considerably under the flame of the candle, so much so, that its light proceeds to a point 234 degrees beyond the north pole, enlightening the whole arctic circle and thereby causing any given point north of the equator of the globe to continue longer in the light than in the darkness, thus giving the longest day, mid-summer, to the northern surface of the earth. The lower part of the globe in this position will be found in darkness. The light from the candle falls short of the south pole by 234 degrees, quite the reverse at the north pole; thus causing mid-winter to all the surface of the earth to the south of the equator. The letter C shows the place of the earth at the autumnal equinox, 23d September. Again, as in the opposite position on 21st March, the candle flame enlightens the globe from pole to pole, causing equal day and night over the world; and lastly, the letter D indicates the earth's position at the winter solstice, 23d December. Here the light from the candle does not reach the north pole, but falls 23 degrees short of it, just as many degrees as the light went beyond this pole in the opposite position; but whilst the light falls short of the north pole, it penetrates 23 degrees beyond the south pole; thus causing mid-winter to the northern parts of the earth, and mid-summer to southern hemisphere. Thus at a cost of a few pence, a simple apparatus may be constructed to illustrate the two-fold motion of the earth-the alternate succession of day and night-with their various lengths, and the change of the seasons, in a way little inferior to that shown in complicated orreries, or other astronomical machinery.

An engraving, similar to the one we here give, will be found in Ferguson's Astronomy, Plate 4th, figure 3d.116

1745.

THE TRAJECTORIUM LUNARE - MARTIN FOLKES, ESQ., and the ROYAL SOCIETY.-According to our memoranda, some time during the month of February 1745, Ferguson took his recently invented "Trajectorium Lunare, and the delineation it had made, to Martin Folkes, Esq., the then President of the Royal Society, on a Thursday afternoon." 117 who expressed great satisfaction at seeing it, and was convinced that it was a new discovery. He took Ferguson with him, the same evening, to a meeting of the Royal Society, and got him to exhibit his machine to the members, and to show how the delineation was projected. At the close of the meeting, one of the members invited Ferguson to dine with him on next Saturday, at Hackney, mentioning that his name was Ellicott, and that he was a watchmaker 118 Vide Ferguson's own Memoir, p. 49.

116 Bonnycastle, in his Astronomy, has an engraving of this simple apparatus, improved, he says, but we can discern no difference in his engraving of the figure from that of Ferguson, excepting in this, the bottom of the candlestick is round and stands on a square table instead of a round one. (See-Bonnycastle's Astronomy.)

117 It may to many appear remarkable that Ferguson, in 1773, when he wrote his Memoir, should have been able to remember the very day of the week that he went to the Royal Society meeting with this instrument. He went to the meeting on a Thursday afternoon, he says; but as the Royal Society meetings were then always held, and we believe, still continue to be held on a Thursday, it would therefore, in this case, require no effort of the memory to recollect the day. (Vide also note 77).

118 The writer of the short Memoir of "JOHN ELLICOTT, F. R.S." in "The Horological Journal," mentions, that "Mr. Ellicott frequently introduced friends to the Society, among others, Dolland, Smeaton, and Ferguson." This, as regards Ferguson, is a mistake. Ferguson in his Memoir tells us that he went to Martin Folkes, Esq., the President of the Society, and that the President introduced him to the Society, in order that he might show and explain his Trajectorium Lunare, and the delineation it had made, to the members; on which occasion, Ferguson and Ellicott appear to have been utter strangers, for Mr. Ellicott, at the close of the said meeting, had to mention to Ferguson that his name was Ellicott, and that he was a watchmaker. This writer makes another mistake -he says, Ellicott who was present," when Ferguson showed his machine to the Society, "stated that he had invented and constructed a similar machine many years before. Ferguson doubting the truth of this assertion, Ellicott invited him to dine at his house at Hackney, and there produced evidence which confirmed his statement," &c. It will be observed that this writer does not inform us of the source whence he learned that Ferguson doubted the truth of Ellicott's assertion." If Ellicott made “the statement," as this writer says he did, it is singular Ferguson does not tell us of it in his Memoir. Again, supposing 66 the statement to have been made, we scarcely think that Ferguson would have doubted the truth of "the statement," -we can imagine in such a case, that Ferguson would express his surprise, a very different thing from doubting a man's

"Accordingly," says Ferguson in his own Memoir, "I went to Hackney, and was kindly received by Mr. John Ellicott, who then showed me the very same kind of delineation, and part of the machine by which he had done it, telling me that he had thought of it twenty years before-viz. in 1725: I could easily see by the colour of the paper, and of the ink-lines upon it, that it must have been done many years before I saw it. He then told me, what was very certain, that he had neither stolen the thought from me nor had I from him." Although Ferguson was therefore not the first who had discovered that "the path of the moon was always concave to the sun," yet he had undoubtedly all the merit of an original discoverer.

THE MOON'S CONCAVE PATH, BY FERGUSON, ENGRAVED AND PUBLISHED. As mentioned in note 75, Ferguson, at the suggestion of Martin Folkes, Esq., and other members of the Royal Society, resolved to publish his delineation of the moon's concave path.119 He made out a new projection on a sheet of paper 343 inches in length, by 6 inches in breadth, giving the absolute motion for a space of 32 days, with a neatly-written explanatory description above and below the delineation, with a dedication to Martin Folkes, Esq., thus:-" To MARTIN FOLKES, ESQ., PRESIDENT OF THE ROYAL SOCIETY, THIS PLATE IS DEDICATED, BY HIS MOST HUMBLE SERVANT, JAMES FERGUSON. PUBLISHED JUNE

26TH, 1745, ACCORDING TO ACT OF PARLIAMENT." This plate was engraved by J. BICKHAM, and was sold by Mr. Senex, at the sign of the Globe, opposite to St. Dunstan's Church, Fleet Street, London. Price 1s. 6d. (See note 75.)120 It is now not known how this

word; in short, since Ferguson makes no mention in his Memoir that Ellicott made such a statement," we are inclined to conclude that no such statement was made. Then, to give Ferguson a surprise, he invites him to dine at his house, and then and there shows him, no doubt to his very great surprise, the same sort of delineation as his own, of the Lunar Orbit, and part of the machine by which it had been projected. As previously mentioned (note 78), Mr. Ellicott, in 1772 dropped suddenly from his chair, and instantly expired. (See Horological Journal, vol. I., pp. 152-154, Memoir of John Ellicott, F. R.S.

119 Ferguson, in a letter to the Rev. Dr. Birch, London, of date 12th December 1752, says, "The instrument was shown to the Royal Society in the year 1745, and a printed scheme of the moon's path, taken from a drawing made by it, was presented to the said Society the same year, being published at the desire of the late worthy President, Mr. Folkes." (See note 115).

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120 In same letter to the Rev. Dr. Birch, Secretary, Royal Society, of date 12th December 1752, he says, My scheme of the moon's path, on a large sheet of paper, is sold by Mr. Senex, at the sign of the Globe, opposite St. Dunstan's Church, Fleet Street, Price 1s. 6d." (See letter in the Appendix).

sheet sold. It has been out of print for upwards of a century. Our fac-simile of the engraving was taken from the copy in the British Museum, by Mr. Augustus Burt, London; the Museum number and mark on which, is, No. 5 f. 7.-On the back of the title-page of Ferguson's first work, a tract, entitled, "THE USE OF A NEW ORRERY" (published about August 1746), we find the following advertisement of this engraved sheet of the Moon's Path:

"A Delineation of the Moon's Real Path in the Heavens, showing that her progressive motion is always concave, both to the Earth within her orbit, and to the Sun on the outside thereof. Price One Shilling and Sixpence." Vide Ferguson's Tract, entitled, "The Use of a New Orrery," 1746-fly leaf.

AGNES FERGUSON born.-To Ferguson, the great event of the year 1745 occurred on August 29th. On this day, his first child was born-a daughter and shortly afterwards was baptized Agnes. On one of the fly leaves of a small pocket Bible which belonged to the Ferguson family, we find the following entry in Ferguson's autograph:

121

"AGNES, born, Thursday, 29th Augt. 1745."

To keep events in harmony with the order of time in which they occurred, we must refer the reader to date 1763, where will be found an account of the "mysterious disappearance" and subsequent life of this unfortunate lady, which, previous to our recent researches regarding her, had been recorded as “a mystery which never would in time be unravelled."

THE ORRERY.-About the end of this year (1745), Ferguson got the large wooden orrery finished, which, early in the preceding year, he, and a turner in wood, &c., had commenced to make. In the Tract which Ferguson shortly afterwards published regarding it, he says nothing about the wheel-work numbers which produced its various motions; but from the account he gives of it in said tract, it showed, with considerable exactness, the following motions and general phenomena, viz.:-The mo

121 This Bible is still in good condition, and is at present the property of Doctor James George, of Keith, in Banffshire, who kindly allowed our esteemed friend, Mr. Robert Sim (of same place), to take a copy for us of the writings on its several fly-leaves, all which shall be noticed in the order of time to which they refer, as also in our addenda. This Bible is 74 inches long, 44 inches broad, and 24 inches thick; and at foot of the title-page is "London: Printed by Thomas Baskett, printer to the King's Most Excellent Majesty, and by the assigns of Robert Baskett, M.DCC. LVII.'

tion of the sun from west to east on an inclined axis, (in the centre of the machine,) and thereby, the motion of the solar spots; the revolution of the planet Mercury; the revolution of Venus, and her diurnal rotation on an inclined axis, which preserves its parallelism during its annual course; thus exhibit

ing her different length of days and nights; her change of seasons; and her progressive, stationary, and retrogressive aspects as seen from the earth.-Also, the revolution of the earth round the sun, and its diurnal rotation on an inclined axis, which preserved its parallelism during its course, consequently, showed the alternate succession and different lengths of day and night throughout the year, and the change of the seasons. The Synodic and Periodic revolutions of the Moon were also shown, and also the diurnal rotation, with the retrograde revolution of the nodes of her orbit, and therefore, all the Eclipses of the sun and moon. On the exterior plate, covering the wheelwork, were two dial-plates, having indexes, pointing respectively, when in motion, to the hours of the day of mean solar time, and to the day of the moon's age, while a small inclined dial, under the earth, showed sidereal time. Directly opposite to the earth rose a shaft that carried an index which pointed out on the great ecliptic circle (as it moved along with the earth), the names and days of the months, and the signs and degrees of the ecliptic. In the tract previously alluded to, which is

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