434 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



FDecember. 



Lowever, was the province and tlie line of study wliich was requisite to 

 ijualify the young engineering graduate for this noble profession. Amongst 

 the more immediate brandies of study for this purpose were to be enume- 

 rated tliose of mechar.ical, topographical, and mineral engineering. An 

 intimate acqunintance with mathematics, a knowledge of natural and me- 

 chanical philosophy, of chemistry ami economic geology, were likewise 

 jiecessary in pursuing the business of civil engineering. 



The stupendous aqueducts, constructed by the Romans, have been com- 

 monly stigmatized as but immense monuments of their ignorance of the sim- 

 plest principles of science, inasnuich as they seem constructed in utter disre- 

 gard of the now universally familiar fact, that water, if left to itself, will find 

 its level ; but the learned Professor showed that the defects in their construc- 

 iion were much more probably owing to the low state of the metallurgic arts 

 in ancient times, and the difficulty if not responsibility, of their providing 

 pumps, pipes, &c., of strength and capacity enough for sustaining the pres- 

 sure of large bodies of water. Modern engineers had, he thought, but little 

 superiority to boast of, in point either of scientific knowledge, or engineering 

 skill. Tlicre was, however, scarcely any one branch of the arts and sciences 

 from which an engineer might not draw important aids in the exercise of bis 

 profession. How chemistry might lend her helping hand, was strongly ex- 

 emplified by the highly philosophical researches of Mr. C. W. AVilliams into 

 the process of combustion, by which the long standing nuisance of smoke 

 seemed likely to be for ever extinguished, and a saving effected of not less 

 than 30 per cent, in the consumption of all fuel employed for engineering 

 purposes, llow a knowledge of jmeumatics might be tnmed to good account 

 was evidenced in the \'arions contrivances for storing and distributing the gas 

 ■R'ith whicli our cities and towns are lighted, and would, he believed, be soon 

 still more strikingly manifested in the atmospheric railway ; for which we are 

 indebted to the same ingenious individual (Mr. C'legg) who invented the 

 greater part of our gas machinery. The Professor stated that he had himself 

 not only investigated with great care the principles of this new system of 

 railway transit, but witnessed several most successful trials made of it, and 

 liad no doubt whatever of its coming, ere long, into most extensive and pro- 

 fitable use. He cited these " modern instances," (liesides others which we 

 lave not space here to notice,) not so much because they were among the 

 most remarkable of their kind, as because they were among the most recent. 

 Although true it was that civil engineering was not made, as it ought to be, 

 a matter of regular study by all embarking in the practice of it, and true also, 

 that it had been hitherto almost wholly neglected as a distinct branch of 

 education in our universities and colleges, yet he felt botmd to acknowledge, 

 and did so with great pleasure, that there were other means and other chan- 

 jiels of acquiring information on engineering subjects, peculiar to the present 

 day, of which engineers did avail thf msclves to an extent which went a great 

 •way to make up — though they could never do so entirely — for the want of 

 early and systematic instruction. He referred particularly, and in terras of 

 great commendation, to the establishment of the Civil Engineers, to its inte- ■ 

 resting and edifying weekly conversational meetings, and to the liberal and 

 extensive circulation of its Transactions. Of the value of such an institution 

 as a sort of storehouse for the communications of engineers on all subjects of 

 interest to their profession, it was impossible to speak too highly. He might 

 cite as an .ippropriate example of this, the account lately furnished to the in- 

 stitution by Mr. Clegg, jun., of the Portuguese viaduct of Alcantara — a work 

 as extraordinary for its magnitude as its expense, having cost no less than 

 about 120,000/. a mile. The scientific periodical press had also rendered 

 most important service to the engineering profession ; in particular the Me- 

 chanics' Magazine, and Ciril Engineer and Architect's Journal. Much valuable 

 information was to be gleaned from the periodical literature of the day, and 

 from such works as those of Smeatou, Tredgold, Rennie, the " Transactions 

 cf Civil Engineering," and other productions. Many were the striking 

 results which might be mentioned of the power of knowledge, where science 

 ■was combined with skill, as might be illustri^ted in the labours of the Earl of 

 Eoss, better known in the scientific world as Lord Oxenstown, who, follow- 

 ing in the steps of Herschell, had constructed the wonderful reflecting teles- 

 cope. It was the business, he conceived, of a civil engineer, to be economi- 

 cal in his works, and to keep down every branch of expenditure as much as 

 possible. 



THE LEVELLING STAFF. 



Sir — Observing in this month's number of your excellent Journal, a notice 

 cf some "improvements" made in levelling instnmients,by Mr. T. Stevenson 

 — I cannot refrain from a few remarks on the too great disposition now 

 prevalent to " improve '' by complication, many instruments which we have 

 already liad much improved by being simplified. I allude more particularly 

 to the levelling stafl', wldch has been made almost perfect by the ingenious 

 method of " self-reading," and which when propi'rly used, in my humble 

 judgment renders any adjusting apparatus worse than useless. 



Inventive ndnds when impressed with improving ideas are, in their 

 anxiety to bring them forth, prone to overlook many attendant circumstances 

 whicli more than neutralize the presupposed advantages, and such, I con- 

 ceive, is the case with Mr. Stevenson, for in the attempt to attain such 

 superlative accuracy by means of his adjusting screw aud clamp, in the 



reading of the stafl!', a certain portion of both the observer's and holder's at- 

 tention is absorbed, which should he entirely devoted to obtaining the exact 

 reading when the staff is in the perpendicular position. A method which I 

 have adopted in practice, and which may not generally be known, ensures, 

 I may say, perfect accuracy, and allows the observer to be quite independent 

 of Lis assistant — is expeditious in the extreme — and may be practised in mo- 

 derately windy weather still ensuring the same accuracy of obsenation. It 

 consists in instructing the stall" holder to firmly and slowly move the staff to 

 and fro in the plane of the olwervcr, the base of the staff acting in its seat as 

 a hinge, — during this motion, the cross wire of the telescope is seen to travel 

 up and down, and up again on the face of the self-reading stafl' — the se- 

 quence of these being reversed in its return motion. The least reading 

 should be always taken down as it is at this point the staff is perfectly per- 

 pendicular. I have found this plan most satisfactory and easy in practice, 

 and I trust the judgment of any practical man will convince him of the supe- 

 riority of it over any complicated adjusting screws which may be applied, 

 and which tend greatly to increase the cx'pense of a most simple and cheap 

 instrument when properly made. 



I am. Sir, 



Your very obedient servant 

 Dublin, 18/A Kuv. 'Willl'^m Bewlet. 



M'. B.'s IMPROVED R.\IL AND CIIAIU. 



Sir — Surely your correspondent \V. B. must be one of those who walk 

 through the world with their eyes shut; it would be difficult otherwise to 

 reconcile the fact of his being " practically engaged in the construction of 

 railways for some years," and his calling the attention of your readers to 

 such an extremely impracticable thing as his " improved rail and chair." 



W. B. starts with the astounding observation No. 1, "that the greatest 

 strength of the rails is not in the direction of the force they are intended to 

 bear." I can only say, if \V. B. has really seen this to be the case, it can but 

 have been on the hues on which he has been " practically engaged." Subse- 

 quently, he admits indeed that " this is assisted a little by placing the chairs 

 decUniug a little inwards ; but which is entirely at the mercy of the workmea 

 employed to lay the rails." Were this true, it would be a sweeping denua- 

 ciation of the whole profession ; but fortunately for engineers, it is not so ; 

 the observation reflects only on \V. B. himself. This important point is no 

 more left to " the mercy of workmen," than is the gauge itself of the line; 

 both are with the same accuracy adjusted with a template, and receive the 

 careful attention of engineers and inspectors. 



Template. 



Chairs and Rails inclined. 



Had W. B. known what was done on all lines but his own, he would surely 

 in very fairness have placed the rails under his barrel in their true position, 

 however much, giving them a vertical direction might help out the argument 

 of his offspring. 



In observations 2 and 3, W. B. complains '■ that there is invariably con- 

 siderable attrition between the rail and chair, and between the joints of the 

 rails," and " that the fixing of the rails is subject to failure from the loosening 

 of the key or wedge ;'' which said observations lead me to suppose that bis 

 practical engagement on railways must be of rather ancient date ; I shall 

 therefore take the liberty of informing him, that in most, if not all, the later 

 methods of laying rails, these inconveniences have been very nearly obviated ; 

 so perfect indeed, in most cases is the connection between the rail and chair, 

 that in instances of partial subsidence, the pins are much more frequently 

 seen drawn from the sleepers and blocks, or these lifted from their beds,thau 

 the rails parted company with, or loose even in the chairs. The latter part 

 of \V. B.'s tliird observation is rather a sly hit at himself. He complains of 

 " a wooden wedge having greater force to sustiiin than it is able without being 

 compressed," and yet he not only uses a wooden wedge himself, but actually 

 compresses it untd it fills a series of notches in the chair ! 



It is not a little singular that with all \V. B.'s acute perception of the diffi- 

 culties and dangers of rolling the usual " irregular forms of the present rails," 

 as evinced in observation No. 4. and with all his practical experience, it did 

 not occur to him that there might be some sUght practical reasons to induce 



