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tidal basins, called, respectively, the high-water and the low-water basins, the turbine wheels being placed between them. The high-water basin is provided with gates opening inward and admitting water from without whenever the tide reaches two-thirds of the maximum; so that for a thirty-foot tide, for example, there would be an inflow of water from the twenty-foot level up to the thirty-foot or high-tide level, the gates closing at the turn of high tide. The gates of the low-water basin, on the contrary, open outward during the last third of the ebb tide, so that this basin is emptying from the ten-foot level down to extreme low tide. There would thus always be a considerable difference in level between the two basins, ranging between ten and twenty feet head, or in the same proportion for other tidal ranges; and by varying the number of turbines in action the amount of power might be fairly well equalized. It has been proposed to instal a plant on this principle on the banks of the Seine, near Havre; but as yet this has not been done. The cost of power produced in this manner is mainly dependent upon interest and depreciation charges; these varying with the value of the land and the magnitude and nature of the controlling and regulating works.

Interest in the development of tidal power has been manifested more than once in Great Britain, where it is generally considered that natural waterfalls are too few and too low to represent much available hydraulic power. As a matter of fact, however, there is much valuable hydraulic power in the British islands, even though it may not be so apparent or so picturesque as in Switzerland or Norway. In a recent discussion of this question, Mr. Ristori has shown that on the west coast of Scotland, in Wales, and in the west of Ireland there are many places where large water-sheds may be found in proximity to suitable storage. sites, and with considerable differences of level within short distances of the storage. The large rainfall of these districts gives assurance of a good supply, and renders the construction of large storage reservoirs unnecessary; while the moderate climate gives assurance of ample power even during the winter season, when the streams in Switzerland practically cease flowing.

Another suggestion for the utilization of hydraulic power comes from the Pacific coast of the United States, where the high cost of coal renders other sources of power of importance. The proximity of the mountain ranges to the coast makes it entirely practicable to secure ample power, hydraulically generated and electrically transmitted at any de

sired point on or near the coast from Southern California all the way up to British Columbia; and this power might well be used to operate a system of electric railways, competing advantageously with steam railroads. Already there are several local electric railways on the Pacific coast deriving their power from hydro-electric stations in the mountains; and, by filling in the gaps and combining a number of feeding stations into one distributing network, the supply could be made equal to the demand at any point. An especial advantage in this system appears in the fact that in electric traction the load on the power stations is only the sum of the loads on the different motors, averaging much less than the sum of their maximum powers, while the capacity of the steam locomotive has to be that of the maximum effort required, even though that effort be demanded but for a very short time.

There has been a revival of interest in the subject of the scientific destruction of municipal refuse, and various cities are discussing with more or less seriousness the desirability of incinerating all the organic refuse produced within their limits. It is now generally admitted that the heat value in refuse is greater than any other value which it possesses, while at the same time sanitary conditions demand that all organic matter be reduced to the inorganic state as promptly and effectively as possible. Ever since the reports upon the performance of the Shoreditch destructors, the idea of obtaining heat and power from the burning of refuse has been a favorite theme of municipal reformers, and in very many instances the generation of power has been permitted to obscure the fact that the matter of prime importance is the destruction of the refuse. This, the main purpose of any system, demands furnaces operated at extremely high temperatures, and one of the most frequent causes of unsatisfactory performance is the failure to maintain a high enough heat to effect the immediate and complete combustion of all the refuse.

Another element of importance has been demonstrated to be the provision of furnaces of ample capacity to deal promptly with the maximum volume of refuse which may be delivered. Any attempt to store accumulated refuse, even for a brief period, is highly objectionable, and the necessity for such an attempt is in itself evidence of the inadequacy of the plant for its location. By the use of properly designed furnaces, planned as to character and dimensions for the especial location which they are to serve, and supplied with powerful hot-blast forced draft, it is entirely possible to destroy all refuse in a complete and inoffensive man

ner. This being made the main question, it is then entirely in order to utilize as much of the heat as possible in the generation of steam; but at no time should the steaming portion of the plant be permitted to interfere with the completeness of the incineration of the refuse. The steam must always be regarded as a by-product, secondary to the matter of the refuse destruction.

An important element in the successful operation of a refuse destructor lies in the matter of the collection of the material and its delivery to the incinerating furnaces. Too often. the collection of garbage and other refuse is in the hands of entirely different persons from those having charge of the destructor station, and united and consistent action. becomes difficult or impossible. Upon this point the success or failure of an otherwise well-planned system may depend; and, unless united and harmonious control of the whole operation is maintained, success cannot be expected. With the observance of these main features, namely, a systematic and uniform method of collection of refuse, a direct and continuous delivery to a properly designed cremator of ample capacity, the maintenance of the highest temperature practicable in the furnace, and a skilful and responsible engineering control - with these, the waste and refuse of any great city may now be effectively and inoffensively disposed of, with such reasonable return in power as shall make the cost a minimum.

In this connection, it is interesting to note that a much greater proportion of combustible is found in the refuse from the poorer localities, while in the wealthier districts adjacent a much lower heating value is found. This may be a matter of relative wastefulness or care; but, be this as it may, the fact is fairly well established.

It may be of interest to call attention to the fact that in engineering, as in other departments of work and activity, the things which are considered of the greatest magnitude and importance are by no means those of the largest cost and difficulty. Thus, the Simplon tunnel, important as it is in connection with the opening of new routes from Italy to the North Sea, is estimated to cost about $15,000,000, or less than onethird of the cost of the New York Rapid Transit Subway. The maximum estimated cost of the Panama Canal, cut to sea-level, is $230,500,000, while the estimates for the new subways in New York City alone, not including that already completed, amount to $250,000,000.

It has been estimated that the works now projected and partially under way in and about New York at the present time will involve the

expenditure of nearly $450,000,000! These works include the Pennsylvania Railroad tunnels and terminal, $50,000,000; the electrification of the New York Central lines entering New York, with the reconstruction of the Grand Central Station, $45,000,000; new subways in Greater New York, $250,000,000; Manhattan, Blackwell's Island, and other bridges, $36,500,000; extension of the New York water supply, $60,000,000; improvement of the harbor and the dredging of the Ambrose Channel, $4,000,000. Similar great expenditures are planned about Chicago. It has been announced that extensive railroad improvements and connections about Chicago, to facilitate the handling of the rapidly increasing traffic, will involve the expenditure of about $200,000,000; while the freight subway, which has been so successfully and unobtrusively built under the Chicago streets, is to be enlarged and extended, it is reported, at a cost of $50,000,000 to $100,000,000.

There are thus contemplated, and already partially under way, in and about two great cities of the United States, engineering works involving an outlay of more than $700,000,000, most of which will be provided from private and corporate resources, and all of which is attracting much less attention than are a few national works of less than onethird the total cost. These are but a few of the works which owe their existence to the development of the applied science of engineering, works which are destined to create values out of all proportion to the expenditures which they are causing, and works which, with their successors, may change the courses of trade, the prosperity of nations, and the conduct of governments.

HENRY HARRISON SUPLEE.

LITERATURE: RECENT BIOGRAPHY.

If one were laying down on general principles the precautions to be observed in the construction of a satisfactory biography, there are three considerations, among others, which it would seem, desirable to take into account. In the first place, literary opinion would agree in the main that success is extremely difficult unless the person to be celebrated went through a career conspicuous by a number of striking, not to say spectacular, incidents. When a classical memoir happens to be written with the follower of some uneventful pursuit as its subject, it will usually be found that his life was marked off from that of the average member of his profession by some circumstances of stirring, even tragic, interest; as, for instance, in the case of Lockhart's Scott. Secondly, it has almost become an axiom that the writer should be free from the danger of the partiality likely to beset one who is closely associated by family ties. A widow, in particular, is supposed to be incapable of the detachment and sense of proportion required for a fair judgment of the character and achievement of her husband. In biography, again, more than in most kinds of literary effort, there is reason to suppose that a preliminary discipline in authorship is a necessary qualification. The beginner may tempt the publishers and the public with a novel or a metaphysical treatise, but the writing of memoirs calls for the knack of a practised hand, both on the architectural side of bookmaking and in the matter of style.

It is fortunate for both critics and authors that generalizations of this kind occasionally come to grief, thereby warning us that the literary craft is not to be constricted by unyielding rules, however apparently reasonable. The two delightful volumes which constitute the "MEMORIALS OF EDWARD BURNE-JONES," by G. B-J.,' defy each of the three conclusions mentioned in the previous paragraph. Burne-Jones himself anticipated that the even tenor of his life would make it an unsuitable subject for biography. He questioned the possibility of writing the life of any but men of action, and said: "You can tell the life of 'New York: The Macmillan Company. London: Macmillan & Co.

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