embody all the facilities that the public can reasonably require. The new bridge will immediately abut upon the existing one, and like it, will consist of three large water spans and one smaller land span on each side of the river; each of the large spans will be about 89 ft. 3 in. long, while the smaller ones will measure 28 ft. The level of the bridge will be 35 ft 6 in. above low water mark, and 23 ft. 6 in. above high water spring tides. The superstructure will consist of wrought iron plate web girders with wrought iron cross bars, and the rail-bearing girders are of the usual North Eastern type. The main girders measure 27 ft. 9 in. centers, 7 ft. 6 in. deep and 2 ft. 6 in wide, while the cross girders-thirty of which are required for the bridge-are 8 ft. centers, 1 ft. 9 in. deep and 1 ft. 6 in. wide. The girders will be carried on four piers, each pier being composed of two cast-iron cylinders carrying a plate brick filling which is surmounted by a massive stone capstone. These cylinders will be sunk to a depth of 30 ft. below the bed of the river. The lower portions of the cylinders will be 10 ft. 6 in. in diameter, but about half way up it is reduced to 8 ft., and finishes with a regular tapering to 7 ft. at the top, upon which is placed a simple moulded cap. The metal will vary from 13 in. at the bottom of the cylinder to 14 in. at the top. The whole structure is characterized by a neatness and simplicity of design which makes it admirably suited for the position in which it is placed, and the traffic it is designed to carry. The scantlings in all cases are, as in all North Eastern work, amply sufficient to carry the heaviest loads that can possibly be brought upon the bridge.-Engineer. THE HE following particulars, descriptive of the Craigentinny system of sewage disposal, were recently given in a letter by an Edinburgh firm of civilian engineers: 1. The acreage of irrigated ground at Craigentinny is 250. 2. The population draining into the stream is fully 100,000. 3. The average quantity of sewage applied per acre was till last year about 11,000 gallons daily, but the Edinburgh water supply has been increased, and probably 15,000 gallons would be more correct now. 4. The sewage is only applied to the land about once every three weeks in rotation, and it is also used during the greater portion of each winter as well as in summer. 5. The sewage is applied for several hours each time-depending on the nature of the soil-four to eight hours or so at a time. 6. The cost is infinitesimal compared with the production, two or three men doing the whole work of flooding the land. 7. The produce consists entirely of grass, which is sold in plots by public roup each spring to the cowfeeders or dairymen, and is cut and carted away by them. 8. The average produce is 30 to 40 tons per acre, and the price per acre varies from about £25 to £45. 9. A great portion of the now irrigated meadows formerly consisted of stretches of land worth perhaps 10. It is an error to as 10. preach to have done in England, that only sandy stretches are suitable for irrigation; as a rule, the better the soil the better the result obtained. 11. The notion of the irrigated meadows creating any nuisance of consequence, or being a source of any specific disease, has long been abandoned as untenable by our most distinguished medical men who have considered the subject, and by Dr. Littlejohn, medical officer of health for Edinburgh. Irrigation, like everything else, is a subject that requires careful consideration in each case, combined with some practical knowledge and experience, and it is probably the want of such caution that has caused so many disappointments and failures in dealing with the question.-Engineer. RAILWAY NOTES. the Berlin correspondent of the Daily RITING on railway accidents in Germany, News draws attention to the condition of the German railways under State management. He says: "Another serious railway accident has occurred on the Belgian-German Frontier, near Herbesthal, on the direct Cologue and London line. A collision took place between a passenger train and a goods train with great violence. Eight persons were killed on the spot, and a large number severely injured. The frequency of serious accidents in Belgium, and especially in Germany, is at last beginning to attract attention here; and the English traveling public should not forget that the lines they mostly use are at present the most dangerous. On returning from Cologne last week, I was lucky enough to miss my train to Berlin, which I heard on the following day had been smashed up near Dortmund, with a large number of killed and wounded, Now that the Prussian railways have become state property, the govern ment adopts the principle of economy in every branch of the railway service. For instance, the number of the line inspectors has been reduced to a minimum, one chief inspector being made responsible for so many hundred miles of line, over which it is practically impossible to give the necessary supervision under only one head. Secondly, when a railway accident does occur, such secrecy is observed that a long time elapses before the public are made aware of the exact number of dead or injured, and the matter is hushed up as soon as possible; and the press having no means of obtaining a true account, pays exceedingly little attention to these terrible disasters-that is to say, unless they happen in England, and then as much is made of them as possible. For the past fortnight not one single day has elapsed but an accident more or less serious has been curtly reported in the German papers as happening on German railways. I hear that the Progressists are going to interpellate the Prussian Parliament concerning the new state management of the railways. One thing certainly is striking, that under the new regime pointsmen only get 1s. 6d. to 1. 9d. per day." UNICULAR RAILWAY.-La Nature gives incerting account of the funicular railway lately brought into use at the Giessbach, for conveying passengers between the pier and the hotel on the mountain side. This line is worked on the same principle as the convenient trams at Scarborough, by which people are carried up and down the cliff, i. e., two carriages are connected by a rope, so that one ascends while the other descends; the excess of weight being supplied to the descending carriage in the form of water. At the Giessbach, the line is a single one, except in a small portion at the middle, where the two carriages pass each other. This crossing is effected automatically. Six wheels of one carriage having all their flanges exterior, whilst those of the other have theirs interior, the rails being adapted in accordance, to give the desired result. A wagon for luggage is worked without the cable, by means of a toothed wheel catching in a rack-rail; this is driven by four men. The carriages have a pinion on the front axle, catching in the rack-rail; also brakes, and a catch which is raised by a counter weight while the cable is tense, but acts in case of rupture. The water is from a reservoir, supplied by the Giessbach fall. This railway is 346 meters long, and the slope in some parts is as much as 28ctm. per meter. A rising carriage filled with (40) passengers may weigh 9,500kg.; and the excess of weight for the other carriage is 1,300kg. The velocity is about 1 méter per second, so it takes 346 seconds (about 6 minutes) to make the journey. more, for whereas the estimates show a necessity for a capital of only 60,000,000f., the company is to be formed with a capital of 100,000,000f. This has given rise to the supposition that there is a design of eventually extending the network in Bulgaria. The negotiations with the Roumanian and Bulgarian governments are said to be already so far advanced, that in both legislatures the law authorizing the company to build, and insuring it a handsome guarantee per mileage, is to be brought in shortly, so that the work may begin next spring. The anticipation may, perhaps, not be realized, but there seems little doubt that the scheme of this railway connection is now seriously entertained. SPE PEAKING of a train which was blown over a precipice on the Wellington and Graytown Railway, New Zealand, on the 12th September last, the following particulars are given in the Melbourne Argus, and are more definite th than any previous account which has reached us: The train was composed of-first, two composite carriages, then the ordinary guard's brake-van, then the Fell engine, then two luggage vans filled with furniture, produce and sundry goods, and, last, the incline brake van, with a guard in it. The wind on the plain was not stronger than usual, there being only an ordinary breeze; but as the train went up the LARGE meeting at Victoria (Vancouver's different spots, where the configuration of the mountain's side very strong gusts were felt at Aland) has passed a resolution declar- hills allowed them to strike the train. Nothing that separation from the Dominion would ing, however, happened, and the train went on be the best course if the government of the all right through the first tunnel, and had latter fails to carry out its obligations with re-emerged through a cutting within fifty or sixty gard to the Pacific Railway. A man army. CCORDING to intelligence from Paris in the quarters, the project of direct railway communication with Constantinople, via Roumania and Bulgaria, has been taken up very seriously. The report of M. de Serres, the engineerin-chief of the Austrian Staatsbahn, who was sent last summer at the instance of the late M. Isaac Pereire, the president of the Paris Committee of the Austrian Staatsbahn, to open negotiations with the Roumanian and Bulgarian governments, convinced those who had taken up the idea, and also the late M. Isaac Pereire, of the feasibility of the scheme. It seems that a separate company, mostly composed of French capitalists, is to take in hand the scheme, and that the necessary capital needed has already been secured by subscription-nay The yards of the second or middle tunnel. This ORDNANCE AND NAVAL. HE INCREASING POWER OF GUNS.-A re TH markable result has recently been achieved by Sir W. Armstrong and Co. in the production of a gun, weighing 95 cwt., discharging a projectile weighing 120 lbs., with a velocity of 2064ft. per second-that is to say, having 3545 foot-tons stored-up energy, or 746.3 foot-tons per ton weight of guns. The gun is an experimental one, and we should suppose that such a result must be exceptional, being, of course, very extraordinary, and a stride in advance even of the 613.5 foot-tons per ton of gun obtained by the 6in. Armstrong, reported in The Engineer of November 5th. At present we speak of this as an abnormal individual result. How much the gun is able the committtee, without after all achieving much, unless an efficient system of instruction is set on foot by the Adjutant-General. M BOOK NOTICES. PUBLICATIONS RECEIVED. ONTHLY Report of the Meteorological Bu- Army, contains: Hollow Brick Foundations, Leon Augoc. Paris; Dunod. M DETAILS-Nos. II. and III. ODERN ARCHITECTURAL DESIGNS AND New York: Bicknell & Comstock. Price, $1.00 This excellent work maintains the excellent character exhibited in the first issue. The style of the designs and the finish in execution make this work invaluble to the young archi Suburban cottages in wood form the illustrated subjects of the two numbers before us. The minuteness of detail leaves nothing to be desired in the way of completeness. to bear as a regular service round we cannot say. The fact, of course, indicates something unprecedented. In recording this we would each. take the opportunity of correcting an expression which may mislead a reader in the article of November 5th above referred to. We there spoke of a delicate point, namely, the question of priority of Armstrong 6in. and Krupp's 15-tect. centimeter guns, whose results we compared together. Speaking from the reports of each lying before us, we considered that the two pieces dated from about the same time. In doing so we unconsciously did injustice to the Armstrong gun; for while Krupp's pamphlets, issued at the Meppen trials, as we understand them, contain the records obtained of their earliest private trials, which took place on December 17th, 1878, the report of the Arm-torial illustration and tables all that can be deThis is an illustrated quarto, giving by picstrong results dealt only with a certain series sired in the way of information about gold and of Government trials. Previous to this, we and silver coins. have now ascertained, a Government trial had taken place on May 2nd, 1878, and private trials as early as December, 1877. This, it will be seen, argues a year precedence for Arm strong as compared with Krupp, which in a question of this kind may mean everything, and should certainly be clearly stated. R OBERTS'S RANGE FINDER AT WOOLWICH. Captain Roberts, R.A., recently described a range finder designed by himself to an Artillery audience, General Turner, C.B., the commandant of the garrison, and his staff being present. This range finder mainly consists of a telescope with large field, such as it is proposed to issue to field batteries, mounted on a tripod stand, with cross lines and prism. The glass is directed at the object, and the prism then applied so as to cause the line of vision to be deflected at a right angle to a staff carried on the shoulder of an assistant, and correctly placed by means of a second small glass and optical square. Numbers are read off, for the use of which the range can be read off a slide rule. The operation is a rapid one for intelligent men. It would not here be fair to compare it with Watkins' or Nolan's systems. It is, at all events, a matter for congratulation that so much interest should be displayed in range finding by combatant officers. The best conceivable range finder might be introduced to THE CURRENT GOLD AND SILVER COINS OF duced to United States standard. is given from 1792 to the present time. alphabetical index is added. A PHYSICAL TREATISE ON ELECTRICITY AND MAGNETISM. By J. E. H. GORDON, B. A. New York: 1880. Price, $7.00. In the present time of rapid progress in practical electrical science, every new treatise is scanned in expectation that it contains something new in the way of exposition of the later recognised phenomena. The great need has, however, been of late a treatise that should discuss collectively the phenomena of electricity and magnetism from the physical standpoint only, as distinguished from the mathematical, and should, moreover, regard the work of the practical electricians as something within the province of accepted theories. The present work seems to accomplish this. Under the head of Electro Statics, all the ordinary experiments of the lecture room in frictional electricity are discussed, together with all the elaborate devices of the philosophers used in their researches. Under magnetism all that relates to magnets, terrestrial magnetism and the delicate methods of measuring and recording the latter. Electro kinetics covers a wider field; and be. ginning with battery cells the author passes to Five chapters are devoted to barometers the consideration of the units of measure and alone, five chapters to thermometers; then foltheir application in practical uses. Electro low chapters on hygrometers, rain-gauges, magnetism and magneto electricity are dis-anemometers, electroscopes and ozonometers. cussed under this heading; also the various Tables for barometers and boiling-point phenomena produced by the induction coil, thermometers are added. secondary batteries and the laws of electro lysis. Electro-optics forms part four and closes the work. Throughout the treatise the works of the leading philosophers are described and their opinions quoted. All varieties of instruments of research are fully illustrated and their objects and uses described. This work is undoubtedly the most complete compendium of electrical science in the English language. RACTICAL BLOWPIPE ASSAYING. By GEO. ATTWOOD, A. I. C. E. New York; D. Van Nostrand. Price, $2.00. Quantitative assaying with the mouth blowpipe is a difficult process. Plattner's voluminous treatise has been followed by the few who have acquired enough proficiency to feel confidence in their results, but even with the most enthusiastic students, the success under this guidance is so out of proportion to that attained with similar effort in qualitative determinations that but few have patience to acquire any considerable skill in determiningthe quantities in their essay. The present treatise, recognizing fully the difficulties of the process, proceeds in the most concise way to inspire confidence in the learner and lead him to adopt sure and available methods to insure success. First, the elementary bodies are mentioned and directions given for their determination separately. This, with the description of the apparatus and reagents constitute the first two parts of the work. Part III is devoted to the assaying of silver, gold, mercury, copper, lead, bismuth, tin, iron, nickle, cobalt and coal. The text is embellished with ninety-eight wood cuts. EGRETTI & ZAMBRA'S DESCRIPTIVE CATALOGUE OF PHILOSOPHICAL INSTRUMENTS. Negretti & Zambra: London. For sale by D. Van Nostrand. Price, $2.50. The peculiarity of this catalogue is that the construction of the apparatus is so far described, and the range of subjects so comprehensive, that the so-called catalogue becomes an exceedingly convenient encyclopedia. An occasional essay on the progress in some department of scientific research increases the usefulness of this handy volume. There are several hundred illustrations distributed through 540 pages of royal octavo text. MISCELLANEOUS. EHMANN'S HOT-AIR ENGINE.-The risks of steam to engines of small power are now and trouble incidental to the application generally recognized. A steam boiler must always have close and personal attention by a for attention and possible dangers, are avoided fairly skilled or practiced hand. These needs by the use of heated air as a source of power instead of steam. sion of air heated to 600° or 800° Fahrenheit is The elasticity and expanand thus to enable a small engine to be driven sufficient to develop an appreciable pressure, up to a moderate power, such as that of a half be obtained, but will require larger diameters or one horse. Larger powers may of course tained by the expansion of the hot air is not of cylinders, as the effective pressure to be ob capable of any great increase. The engine we factured by Messrs. W. H. Bailey & Co., of and effective specimen of its class. The conSalford, Manchester, and is a very well designed struction of the engine is horizontal, the heating apparatus consisting of a brick-built fur illustrate herewith is Lehmann's patent, manu The author suggests a useful check in the way of synthetic assays, which consists in the preparation of weighed quantities of the pure element or elements to be determined, mixed with materials resembling as nearly as possible the ore to be determined. Any loss of the nace. In this is fitted a steel air heater which element sought in the artificial mixture serves may be raised to a dull red heat. The workas a guide to correct the regular assay. Part IV. contains useful tables. The illusing cylinder is fixed outside the furnace, and trations and typography are excellent. The book is designedly of convenient size for carrying while prospecting. A its front part is jacketed by water jacketing. A cold chamber is thus provided in which the expanded air is condensed and contracted to its original volume. The working piston is an TREATISE ON METEOROLOGICAL INSTRU- open plunger, which is made air tight by a MENTS By Negretti & Zambra: Lon-cup-leather packing. As this packing is fixed don. For sale by D. Van Nostrand. Price, in the cold portion of the engine it does not $2.00. suffer from the heat, and will last a long time The fame so justly earned by these makers without attention, whilst at the same time it of scientific apparatus gives weight to their forms a tight and frictionless method of packstatements regarding the instruments employ- ing. It has always been difficult to apply a ed in any department of scientific labor. piston packing in these engines which will For the proper care and use of meteorologi-stand the heat of the air. Any class of packcal instruments, an instruction book is indising, which must be packed by a gland, would pensable, such a treatise is provided with this also offer on a large plunger far too great a minute description of the construction of the proportion of frictional resistance in engines instruments. of such small power as those worked by hot air. The working plunger operates directly upon a rocking lever, to the end of which is attached the connecting rod driving a crank and fly-wheel carried in bearings on the top of the cylinder. A circulating pump to supply the water jacket is fixed on the bed-plate, and driven from a rocking bar by a return crank and connecting rod. The hot air is first expanded in the hot chamber which causes the piston to drive forward, the air then escapes at the end of the stroke, and by passing through a cold chamber is reduced to its former bulk, and may be thus returned to the hot chamber without much back pressure on the piston or plunger. The same volume of air is thus used continuously, first being expanded and then contracted for the working and pack strokes respectively. No foul heated air is thus discharged by the engine, to which there is no exhaust. It is somewhat surprising to note the immense rapidity with which the air can absorb heat and give it up again, as we find that as many as 1000 revolutions per minute have been obtained from the smaller sizes. This power of speed will no doubt depend upon the skillful arrangement and extent of surface of the heating and cooling chambers. This engine appears to be very economical, as the makers state that a 1-horse engine will run for twelve hours at a consumption of 50 lbs. of coke. A great advantage also is that such an engine may be safely left to run itself down, since no damage can ensue to it, as it will only stop when the fire gets to low. In this way Lehmann's engine may be left to run all night without any attendance or the fear of a mishap. When applied to farm or domestic purposes the engine need cost little or nothing to work, as the heat of the stove may be utilized for warming purposes, and even the hot water from the cooling jacket would be found serviceable. A pumping apparatus may be attached to the bed plate of the engine so as to form a compact and serviceable pumping engine. OMETIME ago the executive committee of water closet (except the "trapless " closets) to be trapped. 5. Every trap to be ventilated from its highest point into a pipe running out above the roof, and disconnected from the soil pipe. 6. Joints in iron pipes to be leaded and caulked to rust joints. Joints between iron and lead pipes to be made with tinned iron or brass ferules, soldered. 7. Catch-basins to be built outside of the house wherever possible, and ventilated by a special pipe. 8, Water closets to connect with the outer air by a window or light shaft, and to have a ventilating flue. 9. Avoid pan-closets, and use hopper or improved closets. 10. On the upper floor each water closet to be flushed from a separate tank through a pipe not less than one and one quarter inch in diameter. 11. Catch-basins to be periodically cleaned by the city authorities. Sanitary Legislation.-It is the custom of all cities to control, by municipal ordinance and by supervision, matters affecting the public health. Nothing can more properly come within the scope of municipal legislation than measures regulating house drainage, in order to prevent, as far as possible, the generation and spread of infectious diseases. It is obviously necessary to make the precautions obligatory upon all the people, as their efficacy depends on the general use of them, and it is to the interest of all that they should be universally adopted. Your committee, therefore, recommend that an ordinance be passed by the common council of Chicago embodying the most important of the foregoing recommendations, as follows: 1. That every house which shall be connected with the city sewers, after this ordinance goes into effect, shall have a continuous pipe of not less than four inches inside diameter, running from the street sewer to at least two feet above the roof of the house, without any trap throughout its entire length; the opening at the house wall to be larger than the soil SOMETIME 200, As exition of Chicago ap pipe, to allow for settling. pointed a sub-committee to consider the sub- [NOTE.-As there may be some who will ject of house drainage. That committee con- prefer to use a trap on the house drain or soil sisted of Frederick Baumann, James R. Wil-pipe, this vent pipe may in that case be made lett and Bryan Lathrop. After considerable independent of the house drainage, and be investigation and prolonged deliberation the carried through the house without any opencommittee has embodied its ideas in a report, ing into it.] of which the following is a brief summary of the recommendations made: 1. Concrete the ground under the entire building. 2. Ventilate the main sewers by a perforated cover on every man-hole. 3. Every house to have a cast iron soil pipe, not less than four inches in diameter and onequarter inch in thickness, tarred inside and outside, running from sewer to roof, without a trap, accessible for inspection throughout its entire length, and with as great a fall as possible; the openings for waste and soil pipes in the house walls to be larger than the pipes, to allow for settling. 4. Every sink, wash basin, bath tub and 2. Every sink, basin, bath tub and water closet (except trapless" closets) to be trapped, and every trap to have a vent pipe from its highest point. 3. Joints in iron pipes to be leaded and caulked or rust joints. Joints between iron and lead pipe to be made with tinned iron or brass ferules, soldered. 4. Soil pipes to be of iron. 5. All water closets to be connected with the outer air by a window and ventilating flue or a light shaft. 6. Sanitary inspectors to be appointed, under the direction of the health commissioners, to enforce the observance of the foregoing provisions. |