190 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



I June, 



class streets, 19,061 yards; anil the tliinl class 32,.'jl5 yardj; making a 

 total of 73,803 yards, which will require tlie labour of ■49 able-bodied men 

 to cleanse daily, and if cleansed as above slated, 18 ahle-hoilied men. There 

 are several methods recommended and adopted for cleansing streets — viz., 

 by means of jets of water, (as adopted at Philadelphia), tlie patent sweeping. 

 machine, and hy hand labour. 



Cost of cleansing by means of Jetsof Water, 5\ I. per 1000 yards. 



Patent /«;jchlne KU'l. 



fexperinunls nt Salfnrd) 83<1. 



hand labour (able bodied) 18d. - — — 



[jaiiper hand labour .... '..Md. 



The followin;; is the resiili of expTiments tried by Mr. Chadwick, 

 niemiier of the Board of Health, in I'all-Mall, Loudon, to ascertain the 

 relative cost of the two systems of hand-labour: — 



Tha price for sweepin.; P.dl.Mall was by pauper labruir .^s. lOd. 

 ^^— ^— tree 2s. (I.I. 



The paupers were paid 3.?. lOi/. a-day, the free labonrers 2s. Gil. 



The system of pauper labour has had a fair and impartial trial on the 

 turnpike roads throu^hdnt the kingdom ; and if the opinion of such men 

 as Telford and Macadam are worth anything, it has been jusily con- 

 demned, and generally abandoned on the score of inefTicieucy and costli- 

 ness. 



Street Surfaces. — The best material for the surface of streets has been 

 a subject of much controversy. 



Macadam's system of making and repairing street surfaces with stones 

 broken small, resting upon the subsoil, is erroneous in principle: Tel- 

 ford's, with a solid foundation of sand or other slones, set or pitched by 

 hand, and covered wilh a coating of durable granite, whin, or quartx 

 rock, is much to be prt- ferred ; iti fact I consider the roadway of streets 

 formed with small broken stones totally inapplicable for towns, as being 

 expensive, unhealiliy for the inhabitants, and also as the means of adding 

 very considerably tu the labour of horses in draught. 



The round or boulder stone pavement is also open to objection, as it al- 

 lows the liquid tilili to perforate through the large open fissures into the 

 subsoil, wilh which it becomes saturaied, and in certain states of tlie 

 w eatlier, gives olf offensive exhalations; and as generally constructed, with- 

 out a proper foundation, the stones being irregular in size, yield, in ditfer- 

 cnt proportions to the weight passing over them according to the super- 

 ficial area of the bearing surface of the stones, which form ruts and hol- 

 1 jws, and disagreeable inequalities in the streets. 



But a good pavement may be formed of the round pebbles, provided a 

 foundatiiiu of concrete or other solid material is previously prepared, and 

 the slones carefully sorted, so as to have them of one uniform size. 



As the best and most economical mode of preparing the roadway of 

 streets, I would recommend the square set pavement, composed of granite, 

 whin, or other equally durable stone, in blocks carefully squared, 6 to 

 7 inches deep, 2^ to 3 itches thick, and not exceeding 1 foot in lengib, to 

 be set in the streets in regular transverse courses, about IJ inch asuncier, 

 so as to alford a good foothold for the horses, and the lower part of the 

 cavity between the stones filled up with good sharp gravel, and the upper 

 part mixed with a little asphalle, so as to prevent moisture from penetrating 

 through. 



The foundation I would have prepared with concrete 12 to 18 inches 

 thick, according to the amount of the traftic of the street; it may be 

 formed of gravel, broken stone, or burnt clay, as may be found the most 

 economical, mixed with a proportion of hydraulic lime and sand, and this 

 thrown upon the prepared surface of the street from an altitude and after- 

 wards shaped to the requisite curvature, and of one uniform thickness, 

 will make a sound and durable bed for the st-ts. 



The curvature of a street should form a segment of a circle, with a 

 versed sine of not more than is required ju^t to throw oU' the surface 

 water. The great error in the form of many of our streets is the extreme 

 roundness that is given to the cross section. I consider that a versed sine 

 of four inches in a street thirty feet wide, ample. 



The cost of the dilferent systems are as follows : — 



Macailemized Roads; is. per superficial yard ; if on pitched foundation, 

 6s. 6d. ditto. 



Pebble Paving: 2s. per superficial yard ; if on concrete foundations, is. 

 ditto 



•Srjuare Sets: 4». per superficial yard; if on concrete foundation, Gs. 

 ditto. 



Curb Stones. — The material for curb stones I shonlil prefer of granite, or 

 ether stone equally strong and durable. When set in their places, the face 

 of the stone should he previously wrought to suit the bevel of the wheels of 

 carriages. They should be set level with the crown or middle of the street. 

 If an arrangement could be made so that the curb and channel stones could 

 be formed in one piece of stone, with the channel merely hollowed out at 

 the angle or foot of the curb, so as to receive the surface water, they would 

 make better channels for its passage, and less liable to be deranged. 



Chanml Stoves. — The old channels are so badly constructed as practically 

 to reduce the width of the i.treets some three or four feet; but I have intro- 

 duced an improved method of paving them with square steps, by which 

 means the whole width of the carriage mad can be used up to the curb stones. 

 I have used as a further improvement stones prepared purposely for channels 

 ten inches wide and six inches deep, which makes a better channel, from 

 having but few joints, for the passage of surface water ; but a channel formed 

 out ol the curb stones hollowed out at the angles, would make a better channel. 



Reservation of Tnum Manures. — The whole of the liquiJ refuse of our 

 towns has Uw a long period been allowed to run to waste, and it is not 

 until recently Ihat alirutiun has been turned to its value as a manure for 

 land, and to the practicability of conserving it for that purpose. 



in some of the continental towns it has been practised for a considera- 

 ble period on a small scale, but it has been left to the enlightened men of 

 this country and the present generation to develope plans to carry out its 

 principles and to effect the object. 



It is the general opinion of those scientific men who have turntd their 

 attention lo this subject, that the liquid manure of towns is worth at the 

 minimum 10s. per annum for every inhabitant, and some assign a much 

 higher value to it. 



But if we assume the minimum price at 10s. per head, Chester, with 

 its population, should produce near 12,000/. per annum ; but this of course 

 would not be net income, as itcould nut be obtained without a considerable 

 preparatory outlay and annual expense. 



At Edinburgh, Ashburton, Mansfield, and Manchester, it has been tried 

 on a limited scale ; and it appears from the reports given of their works, 

 with a favourable result; but it is yet to be st en whether, when applied 

 on a general system, such great benefits can be derived from it as those 

 theorists, who have so warmly taken up the question, seem to anticipate. 



In Edinburgh, where it has been practically applied to about forty acres 

 of barren laud, it has enhanced its annual value from 3s. to iOl. and 41)/. 

 per acre ; but the cost of the feeders and the preparation of the land was 

 25/. per acre. 



Mr. Newlands, borough engineer of Liverpool, estimates the sewage 

 water of Liverpool to be worth, at the rate above stated, 185,000/. ; thai 

 if raised by steam-power 200 feet, it might be made to irrigate Oi),000 

 acres of laud in the Vale of Alt, but the cost of the preparation would 

 amount to 600,000/., which he considers quite a bar to the scheme, even 

 if the water cost them nothing. 



He estimates the expense of pumping the sewage to be as great as the 

 supply of water to Liverpool. 



He further states that the sewage of Liverpool would amount to eighteen 

 millinu tons per annum ; that as it could not be applied to land at all 

 seasons, it would require reservoirs to store it up, and they would occupy 

 GOO acres of land. The engine necessary to raise it would be 600-horse 

 power, and the total expense of land, reservoirs, engines, pipes, appa- 

 ratus, &c., would be 15,000,000/., and the annual expenditure 1,225,012/ , 

 which, if applied to 900,000 acres of land (or a square of nearly 38 miles 

 on the side that he calculated) it would fertilize, the prime cost of the 

 manure would be about 1/. 7s. per acre for the manure. 



According to this estimate, the total expense of the works would be 

 about 40/. per head, and the annual expenditure about 3/. 6s. per bead of 

 the population. 



In Manchester the system has been practically tested. The manure is 

 brought from the sewers to the banks of the canal, where it is stored in 

 tanks at 3s. per ton, and the contents of the tanks are transferred, by 

 means of a syphon, info barges that are used to convey it to wherever it is 

 wanted to be applied. 



It is applied to the land by means of canvas hose, and forced, by a small 

 steam-engine on board tlie vessel, to about half a mile on either side of 

 the canal. The cost of irrigating is about Is. per ton ; and it takes three 

 tons to the acre of concentrated manure, diluted with from three to six 

 times its vveight of water. This, according to the opinion of iNIr. Smith, 

 of Oeanston, and other eminent scientific agriculturists, is the cheapest 

 and most effectual way of manuring land — viz., by applying it in a liquid 

 state ; as when manures are applied dry, or in the ordinary way, they 

 must be dissolved in water before they can be appropriated or absorbed 

 by the plants. 



I'he manure, when applied as proposed, in a liquid form, disappears 

 from the surface in about three hours, and cattle will eat the grass on the 

 following day. 



The Liquid Manure Company of Manchester charge for twenty tons of 

 sewage 1/. per acre for irrigating laud, and 6d. per mile additional from 

 the source of supply. It is slated Ihat uear ftlanchestcr a comparative 

 experiment was made of the effect of liquid manure and guano. Onecwt. 

 of the Peruvian guano dissolved in water, was substituted for a ton of 

 the undiluled manure, and applied to ditlerent parts of the field. The 

 superior effect of the liquid manure upon the land was pointed out by the 

 prtiprietor, who was ignorant of the substitution. 



Mr. Higgs's method it appears was brought before the public in the 

 year 184G,and iu the subsequent year it had ihe sauctiou of ihe legisla- 

 ture in an act for putting it into operation in Bermoiidscy, iu the county of 

 Surrey ; but previous to the erection of the extensive works by the act, it 

 was thought advisable to erect experiiiienlal works, where every opera- 

 tion might be fully tested by actual woi king. This was done at Northum- 

 berland Wharf, London, and fully verified the most sanguine expectations 

 which had been formed of its success. These experimental works were 

 visited by many scientific gentlemen, who invariably expressed satisfaction 

 at the results ; they were likewise inspected by the cousulling engineer, 

 and chief surveyor of the iMetropolitaii Commission of Sewers, who, in a 

 report to that commission, say — " Under proper regulations, we believe 

 that the work may be accomplished without anuoyauce to the neighbour- 

 hood, and with considerable advantage to the river Thames, by the inter- 

 ception of solid matter. It appears a simple scheme that deserves eucuu- 

 ragemeut, promising iu its character, and luexpeusive to work." 



