a tenison-rod or bolt of wrought or malleable iron bb. The diameter of each sphere is 8 inches, the thickness of the metal threeeighths of an inch, and the internal diameter of opening of the neck 3 inches. Each sphere is by the inventor termed a "unit," and is connected with its neighbour "unit" or "units" by the hollow neck which is provided with a socket and shoulder, so that a steady as well as close contact is secured, and round the joint thus made a steam-tight iron cap is placed. What are called "slabs" are made up of a definite number of units, all held together by the wrought-iron rods of bolts, and each slab forms a "vessel" containing water and steam, both of which can circulate freely throughout the whole range of units or spheres of which the slab is formed. The slabs may be in any number, according to the evaporative powers of the boilers required; and are placed side by side in a furnace, and connected with the feedwater pipe at bottom, and by a steam pipe at top. The water-level is so arranged that about two-thirds of the spheres in the slabs are filled with water, the remaining third acting as the steam space. The slabs are not placed on the level, but, as shewn in fig. 10, at an inclination. This enables the water to be completely drained off when the boiler is blown out, and has the further advantage of bringing the greatest number possible of the water-filled spheres, directly over the hottest part of the fire, leaving the greatest number of steam-filled spheres at that part of the furnace where ebullition would be least active. The principal points of excellence of this form of boiler are these-first, its almost absolute safety; for while the spheres have actually stood the test of 1500 lb. to the square inch, the practical limit may be stated thus, that the "factor of safety" of a boiler of the best construction of the Lancashire form, with a pressure of 50 lb. only on the square inch, is the same as that of a Harrison boiler at 250 lb. a pressure to which, at least, no agricultural boiler need ever be worked at. Second, although free almost entirely from the possibility of an explosion, the Harrison boiler, if worked at a pressure greater than it ought to be subjected to, acts throughout as its own safety-valve; for, on great pressure, the wrought-iron bolts or rods are so stretched that the connexions or joints between the spheres are so opened that the pressure is at once relieved by the steam or the water escaping. A Harrison boiler may empty itself within such circumstances, but it can scarcely be said to be liable to "burst,” involving by this term all the disastrous consequences attendant upon the bursting of a large boiler of the ordinary construction. The third point of excellence is the extreme portability of parts. A fourth, the readiness with which any part of a boiler can be renewed; and a fifth, the great advantage of adding to a power of a boiler by simply increasing the size or number of the "slabs." But to these advantages we may add a sixth, and this not the least important. All those who have had anything to do with steam boilers know the dangers and inconveniencies arising from the incrustation of boilers. Now, in the Harrison boiler, no-at least very little-deposit of matter or "scale,” as it is called, takes place; all that is necessary to be attended to is to blow out the boiler once aweek—that is, if in regular work-and the spheres will keep themselves quite free from scale. It is needless here to take up space by an inquiry into the causes of the selfcleansing action of the spheres: it is sufficient to know that they are always operative, so that even with the use of very foul water, which would infallibly scale or encrustate wrought-iron boilers, no scale or deposit is made in the spheres of the Harrison boiler. Such is a brief description of the latest form of boiler introduced, and which, according to a very eminent authority, constitutes one of the most remarkable discoveries in boiler engineering." We now turn our attention to the care requisite to ensure safety and economy in the working of boilers. An absurd Yankee story is told of a man, in the course of one of those steamboat races so common in the western waters of America, volunteering to sit upon the safety-value--a dangerous duty shirked by all on board-judging as he said, that Fig. 13. A iron cap, as in the engraving, pierced with holes through which the steam escapes. valuable feature of this valve is the direct action of the weight upon it, without the intervention of any jointed levers, which, as already pointed out, are so apt to get out of order. In fig. 13 we give a drawing of the arrangement of Mr Fairbairn, the eminent engineer, by which all tampering with the weight of the valve is prevented, and by which the valve can be lifted now and then out of its seat to prevent sinking. This good in many respects is so far defective, as it depends upon the care of the attendant. The careful attention of the stocker or tenter to the supply of water to the boiler is absolutely demanded if safety is required. The appliances to guide him in his judgment in this important department of boiler management are numerous-in many cases too numerous. They may be reduced to three-first, the "float or water-feed apparatus and indicator;" second, the "water and steam-cocks or gauges ;" and third, the "water-glass gauge." There is a by no means uncommon notion afloat that if any one of these appliances is alone used, that that is sufficient. Now, let the reader take it for granted that all three are needed in a good boiler designed to be worked safely. The "feed apparatus" of boilers vary much in arrangement; indeed, the name is legion, so many inventors having brought out this and that form. Appliances Fig. 14. αι common one is shewn in fig. 14, where the rod a a is connected with a float which rises or falls with the varying level of the water in the boiler. This is connected at its upper end with a chain which passes over a wheel b, and is supplied at its other extremity with a counterpoise weight c. As the wheel moves partially round, its index or finger point d shews how the water level is in the boiler. This apparatus, however simple, is not to be relied upon at all times, as the rod is apt to stick in the stuffing-box e. We know of no form of water-indicator so efficient as that Fig. 15. known as Haley's, illustrated in fig. 15. The copper float a is screwed upon a hollow spindle b, and to which steam is supplied through a hole at its [upper end, and from it to the interior of the float a, so that the pressure is equal] within and [without. As soon as the VOL. I. water level falls, the float falls with it, and the conical end c drops out of its seat, and allows the steam to pass up the pipe d, and acts upon a whistle placed in e. However efficient a form of feed-apparatus may be, it is obvious that if not attended to it might as well not be there; rather, indeed, it would be better absent, for then no trust could be placed in it. Now, suppose that the attendant screws down the handle of the feed valve, closing it and admitting no water to the pump, the pump might continue to work well, yet no water be supplied to the boiler. The reader may here say that surely no man could be so stupid or blameworthy as to do this: as stupid and as blameworthy things as this are done every day, and being done now may be done again. Let the attendant, therefore, be sure that the handfeed valve is open. Further, let him be sure that the rod a a, fig. 14, is not sticking in its stuffing-box e, for if so the feed will not act. Yet more, he must be positively certain that the force-pump is passing water to the feed-pipe: it may be working obviously enough. This may arise from the "clacks" or valves sticking in their seats, or the pump not drawing. The best form of valve for a pump is the "ball clack," which is not so apt to stick as the conical valve. A good way to start a sticking valve in a pump is to give a few blows with a wooden mallet to the case. To ensure a pump drawing water, it is a good plan to have it provided with a "pet cock." This is a small stop-cock added to the pump and the pipe, by opening which any steam that may have gained admission to the body of the pump may be allowed to escape; or by means of which water may be passed to the pump to enable it to draw, should it have ceased to work. All these remarks shew the importance of attending to all the appliances of a boiler. It is not enough to know that one is working and the other not the whole of them must be working in conjunction. But we have not yet exhausted the list of those appliances: having, however, exceeded present space, we must leave what we have further to give for a future Note. S A Summary of Agricultural Events. THE SEASON AND CROPS. CONSIDERABLE quantity of rain has fallen since the commencement of the month, which has had the effect of reviving the pastures to a wonderful extent, and pushing on the turnip crop, so that even seed, which had lain dormant for some time, has now come up in many instances. A heavy, or even a good crop of turnips is not, of course, to be expected from such late growth, but if we have favourable weather during the remaining part of the season the crop will be of great service for sheep. Harvest operations met with a check from the rains, and we regret to say that there has been a good deal of sprouting where the crops were not secured. The wheat crop, and also barley in several places, is turning out well, remarkably good, in fact, but oats are generally short. The potato crop will be light, and there is some reason to fear a second growth in consequence of the rains. One of the features of the season, caused by the great heat and long drought, has been the unusual prevalence of fires in plantations, moors, &c., some of which have proved very destructive. Everything was like tinder, and it only required a smoker's match to be carelessly thrown aside to set the grass, heath, and trees on hundreds of acres on fire. THE GRAIN TRADE. July closed with falling markets, and although with the beginning of August steadiness did not settle down in the corn trade, yet the month had not advanced far when a reaction in the value of wheat took place, amounting to about 2s. per quarter, which was lost, however, at Mark Lane on the 17th, and the country markets which followed also shewed a similar decline. The quality of the new samples has been remarkably good, 66 lb. per bushel being nothing unusual. Oats and barley have been rising in value. THE LIVE STOCK TRADE. to trade in store stock, and the lamb fairs held in the early part of the month were, therefore, excessively dull, with a decline in prices ranging from 5s. to 7s. 6d. a-head, and even more. Store cattle were unsaleable, and some lots of Irish cattle brought over to England for sale were returned in consequence of the entire absence of demand. The improvement of the pastures consequent on the rains which have fallen of late have tended to improve matters, and a livelier demand has been experienced at some recent fairs. The top prices of beef and mutton have ranged as follow:-At London, beef, from 3s. 10d. to 5d. and 5s. 4d. per 8 lb. ; mutton, 4s. 4d. to 5s. 4d. per ditto. At Newcastle, beef, from 7s. 6d. to 9s. per 14 lb. ; mutton, 6d. to 7d. per lb. At Edinburgh, beef, from 7s. 6d. to 9s. per 14 lb.; mutton, 6d. to 7d. per lb. THE WOOL TRADE. At the London wool sales competition has been rather quiet, and inferior descriptions rd. to 1d. per lb. lower. There has been a tone of confidence in the home trade, especially with regard to good wools; at the same time trade is quiet. THE HEALTH OF STOCK. The principal event in connexion with this subject has been the arrival of large numbers of sheep infected with small-pox at the port of London; and 3700 were condemned to be slaughtered on the spot. All the London wharves have been declared infected. Other cargoes have arrived in suspicious condition, the disease being very general in Holland. AGRICULTURAL SOCIETIES. The show of the Highland and Agricultural Society at Aberdeen was very successful, especially with respect to the exhibition of shorthorns, polled cattle, sheep, and implements. Among the shows held during the month were those of the Yorkshire Society at Wetherby, of the Banffshire Society at Cullen, and of the The state of the pastures put a total stop Queen's County Society at Maryborough. The Garden. IT CEMETERY GARDENING. T has been asserted that a nation's progress in civilization and the arts can be traced by its monumental decorations, and the care bestowed upon the last resting-places of its dead. This saying, however, must only be admitted with wide reservations, for if accepted in anything like its literal sense it would go to prove that the nations of Western Europe, notwithstanding their boasted civilization, actually remained in worse than savage barbarity till the present century, inasmuch as not only the Mahometans and Chinese, but even the most untutored and recently discovered tribes of New Zealand and Northwest America cared more for the graves of their departed than did the most enlightened nations of Christendom. The era of cemetery gardening in Christian Europe may be said to have been inaugurated at Paris in 1804, when the extensive gardens and pleasure-grounds on Mount Louis, which had belonged to Pere la Chaise, the favourite confessor of Louis XIV., were converted into a burialground, intended at first chiefly for those who could afford to purchase a grave and rear a monument. The Cemetery of Pere la Chaise has always been looked upon, not only as one of the grand sights of Paris, but also as exhibiting the beau ideal of what a cemetery should be, and it has greatly influenced foreign visitors, by stimulating in them a taste and desire for cemetery improvement in their native lands. the most obnoxious of rank growing weeds, could scarcely sustain an occasional appearance of irregularly scattered verdure. Our country church-yards were interspersed with unsightly mounds, and covered with the coarsest of grasses, nettles, and other vile forms of vegetation, while not unfrequently they were desecrated by depasturing cattle, sheep, or goats; and so little regard was had for antient monumental stones, that grave-diggers frequently sold them to be re-dressed for new owners, converted into hearthstones, or applied to other purposes for which they or their friends might find them useful. General attention became at length directed to cemetery improvement, by the horrid revelations made in the report of a Government Commission, and by the Cemetery Bill, which was brought into Parliament in 1842. About this time also was published the "Necropolis Glasgoensis," a most admirably written pamphlet, which did great service in the cause; and in 1843 appeared "The Principles of Landscape Gardening applied to Public Cemeteries," by that most voluminous writer, the late John Claudius Loudon (the last of his many useful publications, issued only a few months before his death), in which he gave very full details regarding the proper laying-out, planting, architecture, and after management of cemeteries. For many of the views and recommendations promulgated in this publication, its author incurred In our own country comparatively little a good deal of censure and ridicule; and not attention was devoted to cemetery improve- a few of his schemes were stigmatized as being ment till after the first quarter of the present extravagant, visionary, and Utopian, although century, prior to which most of our city bury- most of them have since come to be very ing grounds were foul pestilential areas, generally approved of and acted upon. crowded with uncared for monuments, and Among his opponents were a then rather often so frequently upturned, that, even numerous class, who had been accustomed, |