would amount to 116,0351. sterling, while the same quantity of paddy being converted into rice by the common method, would produce only 64,7991. The saving, therefore, by these two machines, is more than 50,000l. per annum.

But the introduction of this valuable mechanical agent to the mines of South America, did not take place till 1815; and in the following year a report on the subject was published in the Lima Gazette. After describing this important event, it adds, "Immense and incessant labour, and boundless expense, have conquered difficulties hitherto esteemed altogether insuperable; and we have, with unlimited admiration, witnessed the erection, and astonishing operation of the first steam-engine. It is established in the celebrated and royal mineral territory called the mountain Yaiiricoeha, in the province of Tarma; and we have the felicity of seeing the drain of the first shaft in the Santa Rosa mine, in the noble district of Pasco." They add, "We are ambitious of transmitting to posterity, the details of an undertaking of such prodigious magnitude, from which we anticipate a torrent of silver, that shall fill surrounding nations with astonishment."

It appears that the new world is principally indebted to the agency of M. François Uville for this improved era in their mining annals. This gentleman having found that a large portion of the most valuable mines in Peru were falling into decay, and in some cases totally drowned from

the impossibility of draining them by manual labour, applied to Mr. Trevithick of Camborne in Cornwall, one of the patentees of the high-pressure engine. This ingenious mechanic applied himself with such extraordinary diligence to the subject, that in less than nine months the materials for as many engines were completely ready for their destination. This apparatus, which cost about ten thousand pounds, left Portsmouth in the beginning of September, 1814, accompanied by M. Uville and three Englishmen, to direct the erection of the machinery.

Mr. Trevithick was afterwards employed to superintend the Royal Mint established at Lima, and on his arrival in South America, was received with such enthusiastic gratitude, that the Lord Warden proposed to erect his statue in massive silver. The engines employed were exclusively on the high-pressure principle, and will be found under his patent in the Appendix to the present work. Indeed this appears to be the only engine likely to act with an advantageous effect, the extreme rarity of the atmosphere in those elevated regions, precluding the economical use of the common engine.

We have hitherto viewed the steam engine, when employed as a substitute for animal force, in giving motion to mills, raising of water, and a variety of other employments, all of which, however, are of a fixed and stationary nature. But some progress has likewise been made towards the applica

E

tion of the same power to moveable machinery, and when constructed for this purpose it is called a locomotive engine.

The employment of an internal mechanism to impel waggons on a plane road is of very early date, but the first application of the steam engine to this purpose took place, we believe, in the Royal Arsenal at Paris, towards the close of the last century. From this time till 1802, but little progress appears to have been made in the use of this species of wheel carriage; but about the latter period, Mr. Trevithick commenced a series of experiments on the use of the high-pressure engine for the above purpose; and this, with some improvements, has since been adopted.

When these engines were first tried, it was found difficult to produce a sufficient degree of re-action between the wheels and the track road, so that the former turned round without advancing the vehicle. This was remedied by Mr. Blenkinsop, who, when he adopted this species of conveyance, took up the common rails on one side of the whole length of the road, and replaced them with rails which had large and coarse cogs projecting from the outside. The impelling wheel of the engine was made to act in these teeth, so that it continued to work in a rack the whole length of the road.

An engine of four horses' power, employed by Mr. Blenkinsop, impelled a carriage lightly loaded at the rate of ten miles an hour, and when con

nected with thirty coal waggons, each weighing more than three tons, it went at about one-third

of that pace.

The application of the steam engine to impel carriages on the public roads, has hitherto been considered as a refinement in mechanics, rather to be wished for, than a matter of reasonable expectation. It has however been stated, that a vehicle of this description is now constructing in Ireland, intended as a stage-coach, and it is added, that when loaded with a weight equal to four tons, it will be enabled to advance at the rate of fifteen English miles per hour. But it must, we think, be sufficiently apparent that the employment of this species of prime mover on a common gravel road, would be in the highest degree destructive, and a considerable increase in the toll would be the certain consequence.

In proof, however, that the necessity of employing an iron track-road for these vehicles is not so serious an objection as at first view might be supposed, more particularly in our mining districts, the neighbourhood of Newcastle alone, affords, within an extent of twenty-eight square miles, more than seventy-five miles fitted for this species of conveyance; and it is a well known fact, that there are many situations in which iron rail-roads might be advantageously employed, in which it would be quite impossible to open a navigable canal.

suere may be pieces of timber laid to swim on the surface of the water on each side of the fans, and so contrived as they shall not touch them, which protect them from the force of the waves.

Up inland rivers where the bottom can possibly be reached, the fans may be taken out, and cracks placed at the hindmost axis to strike a shaft to the bottom of the river, which will drive the vessel forward with the greater force.

Query 3. It being a continual expense to keep this machine at work, will the expense be an*wered?

Anwer. The work to be done by this machine will be upon particular occasions, when all other means yet found out are wholly insufficient. How often does a merchant wish that his ship were on the ocean, when, if he were there, the wind would serve tolerably well to carry him on his intended voyage, but does not serve at the same time to carry him out of the river, &c. he happens to be in, which a few hours' work at this machine would do. Besides, I know engines that are driven by the same power as this is, where materials for the purpose are dearer than in any navigable river in England. Experience, therefore, demonstrates, that the expense will be but a trifle to the value of the work performed by those sort of machines, which any person who knows the nature of those things may easily calculate."

M. Duquet appears to have tried revolving