So far in explanation: now for details of trials at the Oxford Show of 1870:

SECTION I.-CLASS 1.

Fixed Steam-engines of 4-horse-power with Boiler complete. £20.

SECTION 1. Class I. For Engines of 4-horse-power with boilers combined.— As already stated, except the condition that the bore of the cylinder should not exceed 74 inches in diameter, and also, as should have been remarked, that during the trial the pressure of steam should not exceed 50 lbs., no limitations as to form or as to arrangements were placed upon the exhibitors of these engines.

It resulted from this latitude that, among the following eleven exhibitors who came to trial, there were three engines, exhibited respectively by Messrs. Clayton and Shuttleworth, by Messrs. Brown and May, and by the Reading Iron Works Company, which were in all respects of the ordinary type of the portable engine, with the exception that they were placed upon stands and not upon wheels.

In one instance, at all events if not in more than one, this variance from a portable engine could be caused to disappear, for the stands were removable and the engine was supplied with arrangements for readily fixing the ordinary wheels and axles of a portable engine; and, indeed, one of the exhibitors brought his engine to trial mounted on its wheels and axles, being in every respect a 4-horse portable engine, a class excluded from trial at the Oxford Show. It is hardly necessary to remark that if we had allowed this engine to be thus tried, there was not a single one of the 4-horse portable engines in the Yard which might not have been entered for the prize. On the matter being laid before the Stewards, they at once decided that at the time the engines were being tried, they must be engines upon stands and not portable engines upon wheels. The other exhibitors who came to trial, eight in number, all brought forward engines with vertical boilers, and, with one exception, the engines themselves were vertical; this exception was that of No. 6793, exhibited by Mr. Eagles, but manufactured, as it appears from the Catalogue, by Messrs. Dennison and Sons, of Orchard Street Works, New-castle-on-Tyne.

It will be seen by an examination of Table I. that the three engines which were provided with horizontal boilers gave the best results, and there is no doubt that had the Reading Iron Works not laboured under the disadvantage of being unable to use their loose feed-water heater, their engine would have exhibited the larger economy of about 15 per cent., due (as has been already explained) to the use of heated feed water, and thus the three engines provided with horizontal boilers would have been still farther ahead in point of economy of any of those provided with vertical boilers.

We consider there are points of merit about a horizontal boiler which it is difficult, if not impossible, to equal in a vertical boiler; and one, and a principal one, of these points is that in a horizontal boiler there is a very large surface of water from which the particles of steam can be disengaged, and thus there is far less danger of the steam carrying up particles of water with it.

This liability of carrying over water with the steam (i. e. of "priming") increases with the amount of steam delivered in a given time, and therefore the exhibitors of vertical boilers were placed during the trial under extremely favourable conditions as compared with those in which they would have been in ordinary working, because the engines were restricted to developing only their nominal power; while in actual work, as has already been stated, they would be urged to a far greater power than this. It is a fact, although a regrettable one, that in engines, as in other matters, there arise fashions, and there is no doubt that for the last few years vertical boilers (vulgarly called "coffee-pots") have come into fashion.

In certain cases, such as on swinging cranes, for which these boilers are very largely used, their form is convenient, and there may be other cases, such, for example, as those where floor-space is extremely limited, in which it may be desirable to use boilers and engines which occupy height rather than breadth and width; but these cases are more likely to arise in crowded printingoffices and in little manufactories in the City, where ground is very valuable, than on farm premises. For the agriculturist's purposes we see nothing beyond the saving of a very few pounds (from 107. to 307.) in the original cost of the 4-horse engine to tempt the farmer to purchase the vertical form in lieu of the horizontal-a dear first economy, looking at the perpetual extra cost of working, as shown by the trials.

With respect to the table which follows, and with respect to that which will be given for Class 2, it may be well to call the reader's attention to the fact, that column No. 9, which shows the total revolutions of the break, is not by itself any indication whatever of the merits of these engines, because these total revolutions depend not alone upon the time during which the engine is capable of running before it has consumed its allotted coal, but also upon the size of the pulleys; and in the same way the succeeding column, No. 10, which records the weight held suspended by the break in the case of each engine is by itself no guide of the power developed, inasmuch as that weight varies inversely as the speeds; but column 11, which represents the product obtained by multiplying the total number of revolutions of the break into the weight held suspended in each case, gives results which truly represent the relative performances of the different engines tried.

On mature consideration as to the most practical way of testing engines and boilers of this class, so that a purchaser might best be able to judge whether a particular engine would suit his requirements or not, we decided with the full concurrence of Mr. C. E. Amos, the Society's engineer, and with the sanction of the Stewards, that instead of a number of persons being allowed to assist, and, if we may use the expression, "nurse" the engine, by oiling various parts, breaking the coal for the stoker, and spending much time in attending to the heat of the feed water, &c., that one man only should drive the engine, stoke

the boiler, and attend to the whole; and it was evident that there could not be the slightest objection to such a course, as the whole attention of the man could be given to the work, inasmuch as he had nothing to do with any machinery driven by the engine, as is generally the case on a farm, where a man is expected to give as much attention as he can to all the machinery in motion.

Unfortunately the Reading Iron Works Company were compelled to dispense with their feed-water heater, as it formed no part of the engine, and required the aid of an extra hand.

This arrangement was therefore carried out with the 4-horse-power engines, with boilers combined, though with the 10-horse power engines, which were independent of the boiler, one man was allowed to the engine, and one man to the boiler, which was one belonging to the Society, and was used for all the 10-horse power engines one after the other.

The steam-pressure gauges of all the boilers were tested by the Society's officers, and a note made as to when the index stood at 50 lbs. pressure, and the boilers were all proved by the Judges to 100 lbs. pressure, (See Table, Section I., Class 1.)

No. 7171. Clayton and Shuttleworth. Fixed Steam Engine of 4-horse-power, with boiler combined. This boiler stands upon good supports, on a cast-iron bed-plate on the ground, which also forms a shallow tank for feed water, from which the feed-pump draws at all times, and into which it returns all surplus water that is not required by the boiler.

The boiler is of the form of an ordinary portable engine boiler, with horizontal tubes, fire-box, and smoke-box.

The engine is an horizontal one, very compactly fitted up on one saddle casting that lies on the top of the boiler, and carries cylinder, guides, and plummer-blocks for the crank-shaft, the fly-wheel overhanging on one side.

This saddle casting is hollow, and takes the eduction steam from the cylinder to the chimney, and at the same time has divisions in it that enable it to receive the feed water from the pump, and heat it on its passage to the boiler, so that the water is well heated after it has passed the pump; this is a material point, for when feed water is heated before the pump draws it, there is always a danger of the pump failing to draw well, and hence the water in such cases is generally kept rather cool, or in fact not heated much more than half as much as it may be, when it is heated after being pumped; thus if the cold water is at 60°, and it is heated 76° = 136°, it is pretty nearly as hot as it can be made if the feed-pump has to draw several feet perpendicular lift, and it is wished that it shall be certain to draw and fill well every stroke, whereas, if the water is heated another 760 = 212° considerable economy is thereby obtained; and as there is always plenty of eduction steam at 212° to heat it, there is good reason for so doing.

The fire-bars of this boiler were very thin, and the spaces narrow, and wo think, in actual practice on a farm, it would be found advisable to use stouter bars; the finer bars undoubtedly enable greater perfection in firing to be carried out, and there was no limit laid down by the Society this year as to size of bars.

The space taken on plan by the engine and boiler is 8 ft. in length by 3 ft. 2 in. breath, with 24 in. extra width for fly-wheel.

The engine worked very steadily, though there was at times a little tremor observable in the fly-wheel. The bearings can be readily oiled, as well as the oil caps to the cylinder, by the use of a step-ladder or tressel of 2 steps.

No. 2. Robey and Co. 7110.-This is an upright boiler with vertical engine attached to it; cylinder at top; 7 inches diameter; 120 revolutions per