28 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[January. 



If is next assumed that the time of filling the barrow must be equal 

 to the time of wheeling over one stage, and returning with the empty 



1' 35" 

 barrow. Hence — - — := 07" (47")the time of filling each barrow. The 



whole time occupied in making the experiments from which this re- 

 sult has been derived is somewhat less than 32 inimites, this being the 

 sum of the observed times in the whole five experiments. 



We need scarcely pause to notice how completely inadequate must 

 be a limited experience of this kind as a standard for estimating either 

 the expense or rate of progress in removing earth by barrows. As 

 well might a traveller estimate his rate of progress from the beginning 

 to the end of the journey, by observing his speed during some parti- 

 cular half hour. As well might a vessel's rate of sailing for weeks, 

 months, or for a whole year be infallibly prognosticated from the in- 

 formation afibrded by a simi)le page of tlie log book. 



We challenge all the examples since the beginning of time, vvliere 

 grand conclusions have been drawn from insuflicient premises, to bear 

 comparison with the instance which our author luis here furnished. 

 Telford, Rennie, Mylnc, .Smeaton, and all the other great engineers 

 under whose guiding genius not a few great earth works have been 

 executed long ere railways were thouglit or heard of, how many a 

 laborious inquiry, and how many a painful lesson would have been 

 saved to you, had the experience been yours, of the half hour during 

 which these imi)ortant experiments were made. 



It is due to our readers, however, to inform them that there are 

 three more experiments, " conducted," say the author, " in a different 

 manner." The difl'erenee consists in this, that these experiments are 

 made upon a number of barrows together, instead of single barrows, as 

 in the first set of experiments. 



We relate this second series of experiments in the author's own 

 words, and we make no comment upon them, as our readers will per- 

 ceive at once that they are equally insignificant in point of extent with 

 the first five which we have noticed at length. 



Experiment 1. — Twenty-four baiTows were filled, wheeled fonvard two 

 runs, and tipped, in thirty-eight minutes and forty-eight seconds ; which is 

 the same in effect, as if they were filled, wheeled /orwar-ils and dachcarck, 

 and tipped upon one nm, during the same time. 



E.Tperiment 2. — Eighteen barrows were filled, wheeled forward one run, 

 and brought back empty again, in twenty-five minutes, and forty-two seconds. 



E.rperiment 3. — Eleven barrows were filled, wlieeled forward upon two 

 runs, and emptied, in eighteen minutes : which is the same in effect, as if 

 they were filled, wheeled forward, emptied, and brought back, upon one 

 nuu 



From these experiments it is determined that 1''37" is " the mean 

 time which elapsed while a single barrow can be filled, wheeled one 

 nm, emptied, and brought back ;" we are then told that 37 barrow- 

 loads can be wheeled on each road per hour. And our author, assum- 

 ing, we suppose, the weight of all earths to be the same, derives from 

 this fact the performance of each single barrow road, and upon any 

 number of these working together. It is obvious that this assumption 

 is most erroneous, as for example, the specific gravities of different 

 soils may be stated thus, common mould 1-4G, sand 1'52, sandy loam 

 1.6, clay or marl 1-712, gravelly sand 1-784, gravelly clay 1-93, com- 

 mon land gravel 2-017, rough water gravel 2-32, common sand stone 

 2*5, lime stone 2-7. 



"Thus, supposing that a man can wheel of common mould 37 cube 

 yards in a day of 10 hours, which accords with the author's statement 

 of his performance, lie would only be able, with the same labour, to 

 wheel 23 cube yards of rough water gravel. And, without multi- 

 plying examples to show the fallacy of any assumed standard, such as 

 the author derives from his experiments, it may be observed, in gene- 

 ral terms, that the quantity which can be wheeled will be inversely 

 proportionate to the specific gravity of the stuff", and not by any means 

 constant for all soils. 



Another error into which the author has fallen, is that of taking 

 25 yards as the invariable length of a run. Our own opinion is, that 

 this is too great a length for a level roud ; but, besides this, it is most 

 important to notice that, in order fairly to apportion the labour of 

 wheeling, the length of each man's run must vary according to its rate 

 of inclination. In practice this is always attended to, the workmen 

 usually being quite expert at fixing the position of the stages or 

 resting-places, according to the slope of the run. 



There is yet a third error which we cannot pass over, namely that 

 of supposing two men always to be employed in filling, during the 

 time of the wheeler's absence, so that one loaded barrow may always 

 be ready for him each time he returns to the filling place. It is evi- 

 dent, and experience, moreover, has shown, that in some soils, such as 

 light sands, a single tiller will keep the wheeler constantly going, 



whereas in others, such as stiff" clays and marls, three and even four 

 men are necessary for the same purpose. 



Of such consequence, in an inquiry of this kind, are the particulars 

 which, as we have seen, the author has omitted to consider, and so 

 fidlacious are the general assumptions in which he has indulged, that 

 we cannot refrain from expressing our decided disapprobation of this 

 second part of the work. 



We have only further to remark, that with all these faults in his 

 own work, it is scarcely to be bcrne that such a lofty contempt should 

 be evinced by the author for all that has ever been written before on 

 this subject. Certain we are, and we are happy to say it for the 

 honour of the profession, that there are not wanting many, many prac- 

 tical men, who, if they have never nritkn on the subject, contain in 

 their own heads, or perhaps in the shape of private memoranda, such 

 a complete acquaintance with the system of barrow work, that they 

 can predict accurately, on examination of the locality, everv circum- 

 stance of expense, time of execution, number of men and quantity of 

 materials required, in any particular work. 



This, we presume, would indicate at least as much knowledge of 

 the subject, in all its bearings, as the author of this inquirj' could pos- 

 sibly imagine any person capable of acquiring from the perusal of his 

 work. But how different in value must that knowledge be which is 

 obtained by the practical experience of years, from that which is based 

 upon the experiments of a few hours' duration. The information of 

 the practical man consists of gross results, with all the attendant cir- 

 cumstances of which he is, or ought to be, acquainted ; and his method 

 of arriving, where necessary, at the separate details, is really ana- 

 lytical, and so directly opposed to the process of establishing gross 

 results from separate experiments in detail. 



LITER.\RY NOTICES. 



A \ery able work " on the Law and Practice of Letters Patent for Inven- 

 tions," by Thomas \Vebster, Esq., has just been published, we shall notice this 

 work in the next month's Journal. 



Mr. W'hishaw's long expected work on the Railways of Great Britain and 

 Ireland has at length appeared. We received it so late in the month that it 

 precludes our examining it witli the attention which it deserves, we must 

 therefore postpone our remarks, excepting so far as saying, that it contains 

 several engravings of Locomotive Engines, all the rails in use, and other de- 

 tails connected with railways, very heautifiUly executed ; with valuable tables 

 showing the results of practical experiments as to the actual working of 

 EngUsh Railways. 



The History of the London and Bu-mingham Railway, by Lieut. Leeount, 

 is a republication of his interesting and valuable contributions to Roscoe's 

 illustrated work on that subject. 



The Building-ground Calculator, by E. W. Garbett, Arcliitect, contains a 

 series of Tables for ascertaiuing the value of Land per acre, when di\ided out 

 into plots of various depths from 100 to 300 feet, at prices from 5irf. to 14*. 

 h\d. per foot frontage, or i'lO to Jtl05 per statute acre. 



NEW IN-VENTIONS AND IMPROVEMENTS. 



Improvements in the constrnciion of steam boilers and engines, and of locomotive 

 carriages : patented hy Frank HlU's, of Depfbrd, manufacturing chemist, No- 

 vember 5, 1840. — These improvements are numerous and difficult to explain 

 without the illustrative engravings; a tolerable idea of their nature, how- 

 ever, wdl be conveyed tiy the following list of the ten claims ;— 1. The em- 

 ployment of a series of vertical tubes partly filled with water, and having 

 small pipes passing down their centres, forming passages for smoke or heated 

 air. 2. The employment of a series of vertical tutes which are closed and 

 unconnected at the'top, and open at the lower end. which communicates with 

 a chamber, or series of chambers, partly filled with water ; and which tubes 

 have small pipes passing up their centres, for the purimse of conveying the 

 steam to the boiler with which they are connected. 3. The use of flat cham- 

 bers connected by means of pipes, filled w ith water, the upper portion of such 

 chambers, forming steam chambers. 4. The employment of wooden felloes 

 to wheels used for locomotive and other carriages, which felloes are I'uclosed 

 between tw o vertical wrought iron rings, to which the spokes of the w heel are 

 welded. 5. The employment of hollow anns, which are open at the ends on 

 which the wheels revolve, and through which opening the driving shaft 

 passes. 6. The employment of collars or enlarged pieces running in bearings, 

 w liich have a groove and are connected with the brass containing oil, in order 

 that a rcgidar supplv may be afforded to the working parts requiring the 

 same. 7. The metliod of filling up the space between the arms of the (Hero's) 

 engine. 8. The method of reversing the motion of the engine by employing 

 two sets of arms, w ith other apparatus hereafter described. 9. The mode of 

 inserting a wooden block or other slow conductor of heat between the tube 

 which commuuicites the motion .ind the driving shaft. 10. The mode of 

 imparting motion to an engine shaft, by means of an arm or crank being 



