312 iiEroRT — 1870. 



The results of the aulhor's experiments may be summed up as follows: — 



1st. The admission of cold air above the fuel in quantities sutKci(.^nt for the com- 

 plete combustion of the iutlammable gases is in most cases attended with loss of 

 etliciency, even if such admission takes place in jets over the whole surface of the 

 fuel. Smoke, however, is considerably reduced. 



2nd. By the motion of the air over heated surfaces, and its consequent rarefac- 

 tion and increase of velocity when issuing from orifices in the arched bars, much 

 more perfect chemical union with the iuilammable gases is insured ; the flame is 

 rendered less luminous, but its temperature is increased ; the radiation of heat is 

 diminished, and the furnace door becomes less hot. Smoke is almost entirely 

 prevented, and a higher rate of efliciency is attained. 



The author then proceeded to explain the great diHiculties in the way of work- 

 inf furnaces economically by hand tiring, and stated that Stanley's patent machine 

 for supplying coal to furnaces by means of horizontal fans, well known twenty 

 or thirty years ago, but now limited in its application to a few manufactories in 

 Yorksh'u-e, was probably the first apparatus for mechanical firin"- e^er made. It 

 was difficult to understand why this machine, which with all its imperfections had 

 been used in almost every mill in Lancashire until the new system of boilers was 

 introduced, should be found in Leeds still at work in the crude form in which the 

 ori"inal inventor had left it. This being the only feeder which rained down the 

 fuel evenly on every part of the furnace, involved a principle which was clearly cor- 

 rect ; but to render it efficient it required provision to be made for the combustion 

 of the gases thus uniformly set free. Such desideratum the author stated had been 

 supplied by combining with it the central arched bars. This arrangement, and 

 the improvements made upon the machine itself, had given the following satisfactory 

 results. The entire apparatus, consisting of a self-feeding furnace emitting no 

 smoke, comprised considerably fewer woi'king parts than any of the old machines. 

 It had now assumed a form capal)le of being manufactured at less than one-half 

 the cost of those mechanical stokers in which the fuel had a progressive motion 

 towards the back, and the imperfections of which were principally attributable to 

 the difficulty of regulating the admission of air through the bars at the back of the 

 furnace. 



The efficiency of the combined apparatus above that of the arched bar furnace 

 when fired by hand had been found by careful evaporative trials to be 9G90 per cent. 



In conclusion the author stated that a feeder and furnace constructed on the 

 principles advocated had been in successful operation day and night for nearly five 

 months at the works of Messrs. Earles and King in Liverpool. 



So7ne Hemcirls on ilie extent to xvlt'u-h e-vht'inc/ Worls and Pi-actlce militufe 

 against the Profttahle Utilization of Sewage. Bn Jonx Lailky Dkntox, 

 lil. Inst. C.E., F.G.S. 



This paper points out that although the sewers of towns were not designedly 

 made leaky, thev were not constructed of a material and in a manner to secure 

 their being" water-tight, while in many cases the subsoil-water was intentionally 

 admitted. The original "(Tcneral Board of Health " recommended that all sewers 

 should be water-tight, and that there should be a separate system of pervious 

 channels for the removal of subsoil-water, which, it was stated, could be readily 

 made to discharge their contents into the sewers when required for flushing or 

 dilution. The consideration of these very important points is of little avail in 

 those numerous towns where a complete system of sewerage woi'ks have been 

 carried out, as the difficulty and expense of altering them would negative any such 

 proposition; but it will be of gieat value iji infiuencing the character of works yet 

 to be performed in small towns and villages where no systematic provision exists, 

 and in places where an alteration of existing sewers is practicable at a moderate 

 cost. 



To show to what extent existing leaky sewers, admitting subsoil-water, will 

 allow of the passage of sewage out of them into the surrounding soil is most diffi- 

 cult j but the fact must commend itself to all, that, under certain conditions, a 



