duced the late George, Earl of Macclesfield, to appoint him Assistant Observer in his observatory at Sherburn Castle." Bartlett was born at Stoke Talmage, in Oxfordshire, August 22nd, 1721, old style, and was in his fifty-fourth year at the time his picture was taken. In the print, Phelps is represented as standing and looking through a telescope, while Bartlett is sitting by him with his tablets, or a sheet of paper, in the one hand, and a pen in the other, ready, seemingly, to note down what his associate may announce. There is a penetrating eagerness and sagacity in the eye and general aspect of the old man; and that of the other is also a striking head, with a less keen and vivacious physiognomy than Phelps, but more massive, and indicating, perhaps, more a meditative and calculating mind. In a

manuscript note on the back of the copy of this print, which belongs to the Astronomical Society, it is stated that "Phelps was the person who, on the 23rd of December, 1743, discovered the great comet, and made the first observation of it; an account of which is contained in the Philosophical Transactions, but not the name of the observer." The comet of 1758, so famous in consequence of its return having been predicted more than half a century before by the great astronomer Halley, was also, it may be remarked, first perceived by an observer in а humble rank of life. It was on the 25th of December in that year that the luminary in question was detected with only the naked eye, at Prohlis, near Dresden, by a Saxon peasant of the name of PALITZCH, at a time when all the greatest astronomers in Europe were seeking for it in vain with their telescopes. Nor did Palitzch owe his discovery merely to his superior powers of vision. peasant was really an astronomer. "George Palitzch," says Lalande, "born in the obscure condi

This Saxon

tion of a common labourer, had succeeded both in finding happiness in his humble lot, and in acquiring various branches of knowledge which are rarely found possessed by men of higher stations who have had the advantage of a careful education. More in the way of being struck with the spectacle of the heavens than if he had lived in a town, he had by his own efforts studied and made himself master of astronomy, as well as those parts of geometry, such as plane and spherical trigonometry, upon which it depends. By the exertion of a meritorious economy, he had formed for himself an observatory, furnished with the instruments most important for the pursuit of his favourite study. Few opportunities of making interesting observations escaped him; and notwithstanding this his occupations as an agriculturist were duly attended to. Natural History and Botany were also among the studies in which he took great delight; and he had a very well-arranged cabinet of natural productions, as well as a garden full of rare plants, which he carefully cultivated. He was distinguished by such exceeding modesty, that he always refused even to give any details of his life, notwithstanding they must have been so full of interest. Such was the astronomer and philosopher Palitzch, to whom was reserved the honour of being the first of all the astronomers of Europe in the discovery of the return of this anxiously expected comet." Palitzch, we may add, who was born in 1723, continued to cultivate astronomy, as well as his garden and his fields, for many years after this event-and died at last in his native village in 1788. He had been for some time a corresponding member both of the Royal Society of London and of the Imperial Academy of St. Petersburgh.

CHAPTER XIII.

Discovery and Improvement of the Steam Engine-James Watt.

ALL the inventions and improvements of recent times, if measured by their effects upon the condition of society, sink into insignificance, when compared with the extraordinary results which have followed the employment of steam as a mechanical agent. To one individual, the illustrious JAMES WAtt, the merit and honour of having first rendered it extensively available for that purpose are pre-eminently due. The force of steam, now so important an agent in mechanics, was nearly altogether overlooked until within the two last centuries. The only application of it which appears to have been made by the ancients, was in the construction of the instrument which they called the Æolipile, that is, the Ball of Æolus. The Æolipile consisted of a hollow globe of metal, with a long neck, terminating in a very small orifice, which, being filled with water and placed on a fire, exhibited the steam, as it was generated by the heat, rushing with apparently great force through the narrow opening. A common teakettle, in fact, is a sort of Eolipile. The only use which the ancients proposed to make of this contrivance was, to apply the current of steam, as it issued from the spout, by way of a moving force—to propel, for instance, the vans of a mill, or, by acting immediately upon the air, to generate a movement opposite to its own direction. But it was impossible that they should have effected any useful purpose by such methods of employing steam. Steam depends so entirely for its existence in the state of vapour upon the presence of a large quantity of heat, that it is reduced to a mist or a fluid almost immediately on coming into contact

either with the atmosphere, or anything else which is colder than itself; and in this condition its expansive force is gone. The only way of employing steam

with much effect, therefore, is to make it act in a close vessel. The first known writer who alludes to the prodigious energy which it exerts when thus confined, is the French engineer Solomon de Caus, who flourished in the beginning of the seventeenth century. This ingenious person, who came to England in 1612, in the train of the Elector Palatine, afterwards the son-in-law of James I., and resided here for some years, published a folio volume at Paris, in 1623, on moving forces; in which he states, that if water be sufficiently heated in a close ball of copper, the air or steam arising from it will at last burst the ball, with a noise like the going off of a petard. In another place, he actually describes a method of raising water, as he expresses it, by the aid of fire, which consists in the insertion, in the containing vessel, of a perpendicular tube, reaching nearly to its bottom, through which, he says, all the water will rise, when sufficiently heated. The agent here is the steam produced from part of the water by the heat, which, acting by its expansive force upon the rest of the water, forces it to make its escape in a jet through the tube *. The supply of the water is kept up through a cock in the side of the vessel. Forty years after the publication of the work of De Caus appeared the Marquis of Worcester's famous 'Century of Inventions.' Of the hundred new

In the same work De Caus proposes another apparatus for raising water, simply by the pressure upon its surface in a close vessel, of the air rarified by the heat of the sun. This process may be often observed taking place on a small scale in what is called the Fountain Inkglass, in which, in a warm day or a heated room, the liquid will be forced up sometimes to the very lip of the spout, by the expansion of the superjacent air within the

vessel.

discoveries here enumerated, the sixty-eighth is entitled' An admirable and most forcible way to drive up water by fire.' As far as may be judged from the vague description which the Marquis gives us of his apparatus, it appears to have been constructed upon the same principle with that formerly proposed by De Caus; but his account of the effect produced is considerably more precise than what we find in the work of his predecessor. "I have seen the water run," says he, "like a constant fountainstream forty feet high; one vessel of water rarified by fire, driveth up forty of cold water." This language would imply that the Marquis had actually reduced his idea to practice; and if, as he seems to intimate, he made use of a cannon for his boiler, the experiment was probably upon a considerable scale. It is with some justice, therefore, that notwithstanding the earlier announcements in the work of the French engineer, he is generally regarded as the first person who really constructed a steam-engine.

About twenty years after this, namely, in the year 1683, another of our countrymen, Sir Samuel Morland, appears to have presented a work to the French King, containing, among other projects, a method of employing steam as a mechanic power, which he expressly says he had himself invented the preceding year. The manuscript of this work is now in the British Museum; but it is remarkable that when the work, which is in French, was afterwards published by its author at Paris, in 1685, the passage about the steam-engine was omitted. Sir Samuel Morland's invention, as we find it described in his manuscript treatise, appears to have been merely a repetition of those of his predecessors, De Caus and the Marquis of Worcester; but his statement is curious as being the first in which the immense difference between the space occupied by