[Footnote 117: Stuart 'On the Steam-Engine,' p. 141.]
The Perrier of 1779 was related to the Perrier of the Pompe-à-feu engine-building works of 1836, and his nephew took the Trevithick engine from Paris to a coal mine not far from Brussels, but not fully understanding the use of the balance-bob--the woodwork for which had not been completed in Paris, though all other parts had been fully erected--did not find it easy to manage the engine. The writer viewed Perrier's move as an infringement of the agreement between him and Edwards, the partner of Perrier and Chaper, and therefore declined to take any further interest in the engine.
Mr. Edwards had before that been a partner with Woolf, in a small engineering works in Lambeth; and the writer had also before that been a pupil of Woolf's, in the works of Messrs. Harvey and Co., of Hayle.
The drawing of 'La Belle Machine' (Plate XIII.), of 1836, serves not only as a record of that time, but also in conjunction with the drawing of Dolcoath engine of 1816, enables an engineer to form a sufficiently correct idea of the Wheal Towan engine and boilers of 1827, which in effective duty is scarcely excelled by the best pumping engines of the present day.
The events connected with those Paris engines bring together the engineering works of Watt, Proney, Perrier, Trevithick, and Woolf, in the person of his once partner, Edwards. The writer, when constructing 'La Belle Machine,' had not the slightest knowledge of those links, and heard the name and repute of his engine by the following chance:--
In 1838 a passenger leaving the train of the Great Western Railway at Drayton Station, asked the writer's permission to walk on the line and examine its construction. During a short conversation he mentioned the having purchased at a sale in France the drawings of an engine known as 'La Belle Machine,' representing the Cornish high-pressure expansive steam pumping engine:--_a_, steam-cylinder, 48 inches in diameter, 8-feet stroke; _b_, steam-pipe from boiler; _c_, regulating steam-valve, double beat; _d_, regulating rod and handle for steam-valve; _e_, expansive steam-valve, double beat; _f_, balanced lever and rod for opening expansive valve; _g_, expansive clamp on plug-rod, with regulating rod and thumb-screws; _h_, cataract-rod for relieving expansive valve-catch; _i_, quadrant relieving the catch; _j_, plug-rod; _k_, equilibrium valve, double beat; _l_, clamp in plug-rod to close equilibrium valve by its action on the handle; _m_, balanced lever and rod to open equilibrium valve; _n_, quadrant and catch relieving equilibrium valve by the action of cataract-rod; _o_, regulating slide on cataract-rod; _p_, equilibrium steam-pipe conveying steam from the top to the bottom of the piston; _q_, exhaust-valve, double beat; _r_, clamp on plug-rod, closing the exhaust-valve by its descent on the handle; _s_, balance lever and rod, opening exhaust-valve; _t_, quadrant and catch, relieving equilibrium valve by the action of cataract-rod; _u_, regulating slide on cataract-rod; _v_, exhaust-pipe to condenser; _w_, Y-posts for carrying the gear. The steam in the boiler was from 40 lbs. to 50 lbs. on the square inch above the atmosphere.