viii.]

GRIFF ENGINE.

105

The water was raised from a depth of fifty yards, in three lifts as shown in the margin (Fig. 22). The object of dividing the pump-work into three parts was to ease the pressure on the pipes. "If we endeavour to do it in one lift," says Desaguliers, says Desaguliers, "we shall burst the lower pipes, unless they be of iron, which will be costly; but

FIG. 21.-VALVE-GEAR OF GRIFF ENGINE.

wood will serve very well if we divide the work into three lifts of fifty foot each." 1

Regarding the performance of this engine, Desaguliers states that it "did discharge as much water as did before employ more than fifty horses, at an expense not less than 9007. a year; whereas the fire in coals,

FIG 22.-PUMPS OF GRIFF ENGINE.

attendance, and repairs, did never cost more than 150l. a year in this engine."

In treating of the power of the engine, Desaguliers incidentally mentions the method of calculation followed by Newcomen. "Mr. Newcomen's way of finding it," he says, "was this: From the diameter [of the cylinder] squared he cut off the last figure, calling the figure on the left hand long hundreds, and writing a cipher on the right hand, called the number on that side pounds; and this he reckoned pretty exact as a mean, or rather when the barometer stood at 30, and the air was heavy. Then he allowed between a third and a fourth part for what is lost in the friction of the several parts and for accidents: and this will agree pretty well with the work at Griff engine, there being lifted at every stroke between two-thirds and three-fourths of the weight of the atmospherical column pressing on the piston.'

"2

Though the metalliferous mines in some districts were much in want of more powerful draining machinery, the high

1 Experimental Philosophy, Vol. II. p. 482.

2 lb.

VIII.] FEW ENGINES BUILT IN CORNWALL.

107

price at which alone they could obtain a supply of fuel, operated as a great check to the employment of fire engines. The second engine in Cornwall was erected at Wheal Fortune, in Ludgvan, in 1720.1 Shortly afterwards another engine was built near the North Downs, at Huel Rose, seven or eight miles from Truro, by Mr. Joseph Hornblower, who was sent into Cornwall on purpose.

Hornblower was a native of Bromsgrove, in Worcestershire, or its vicinity. He was by profession an engineer. 'How he became in any way connected with Newcomen," says Mr. Cyrus Redding, a descendant of Hornblower, "must have arisen from the latter being at Bromsgrove, where he, Newcomen, visited a Mr. Potter who got him to build one of his newly-invented engines at Wolverhampton, in 1712.” 2

The cost of coal in Cornwall, however, presented such an obstacle to the use of fire engines, that few were employed there previous to the remission by Government of the duty on coal consumed by minedraining engines. According to Price there was only one fire engine at work in this county about 1740.3

1

"The Statistics of the Copper Mines in Cornwall," by Sir Charles Lemon, Bart., in the Journal of the Statistical Society of London, Vol. I., p. 66.

2 Yesterday and To-day, by Cyrus Redding, London, 1863, Vol. I., pp. 128-9.

3 Mineralogia Cornubiensis, London, 1778. Introduction, p. xiv.

CHAPTER IX.

CONTINUED SPREAD OF THE USE OF ATMOSPHERIC ENGINES.-DEATH OF NEWCOMEN.

THE first atmospheric engine on the Continent was built by a Mr. Potter, an Englishman, at Königsberg, in Hungary, about 1723. It is described and figured by Leupold, in the second volume of his Theatrum Machinarum Hydraulicarum, published at Leipzic in 1725. The engine was very much admired, and Potter 1 Theatri Machinarum Hydraulicarum, Tom. II., Leipzig, 1725, p. 94.

Leupold also describes a form of single-acting high-pressure steam engine, but though proposed and even tried at different times, this class of engine was of an imperfect type and never came into use.

The steam engine invented by Sir Samuel Morland in 1682, which appears to have been designed for working his patent forcing-pump, probably belonged to this class. The only mention he makes of it occurs in a small treatise preserved in the Harleian collection of manuscripts at the British Museum, No. 5771, entitled, Élévation des Eaux par toute Sorte de Machines réduite à la Mesure au Poids et à la Balance, présentée à sa Majesté Très Chrétienne par le Chevalier Morland,

CH.

IX.] JOHN POTTER, AGENT OF PATENTEES.

109

was regarded as its inventor. Leupold himself had not seen it, and he states that some parts of the sketch which he gives must be understood to be rather his own idea than an actual representation of the mechanism.

A curious advertisement from the Newcastle Courant of January 27th, 1724, shows that an agency for the erection of atmospheric engines was established in the North of England by the patentees at this date. It is as follows:

"This is to give notice to all gentlemen and others, who have occasion for the fire engine or engines for drawing of water from the collieries, &c., to apply to Mr. John Potter, in Chester-lestreet, who is empowered by the proprietors of the said fire engines to treat about the same." 1

Whether the above Mr. Potter was the individual who erected the engine in Hungary we are not informed, but it seems highly probable that he was.

No records of any engines built by Potter in the Newcastle-on-Tyne district have been preserved, so far

Gentilhomme Ordinaire de la Chambre Privée, et Maistre de Méchaniques du Roy de la Grande Bretagne, 1683.

Sir Samuel Morland had been sent to France to assist the French king with his water-works, and his idea of employing high-pressed steam to raise water (like that of Hautefeuille to use gunpowder, and probably also that of Huyghens to use the atmospheric pressure acting on a piston) was doubtless brought forward in connection with the many schemes suggested for supplying Versailles with water from the Seine, which was at length accomplished by the erection of the Great Machine of Marly.

1 Brand's History of Newcastle-upon-Tyne, Vol. II., p. 686, note.