The same mode of estimation for a lock of 11 $7,019 50 $7,812 00 stone may be procured at every point where its use is Other items the same as on the preceding page 1,387 00 required, at an expense not greatly exceeding its ordinary cost. At Erie there will be no difficulty, as stone of an unexceptionable quality is found at several places in that vicinity. At Walnut creek also, a stone which it is believed, will answer very well for the plans of the aqueduct at that place, is found in layers of 10 or 11 inches in the shallow water of the lake. From either of these localities stone may be furnished by a land car- Aqueducts. A variety of modes have been discussed, riage of four miles, for the works on Elk creek. For for the great aqueducts of Elk and Walnut creeks-dif those in the Conneaut valley it is thought that stone offering chiefly in the materials and construction of the a suitable quality may be found on Fetterman's run, and trunk. One mode of construction would consist of a probably near Jenk's mill, or in Jackson's gully; at all simple wooden trunk, laid without any artifice upon events, it is highly probable that the material may be ob- piers of masonry; but this, as it requires a great number tained from one or other of these localities for all purpo- of piers, would be altogether unadvisable, in a case ses, except that of the face work and coping. Under where the the piers themselves constitute so considerathese circumstances the cost of masonry will vary at ble a portion of expense. Another mode admits a large different points of the route, very nearly at the follow-space between the piers, and gives intermediate support ing rates. At Erie and Walnut creek, good ordinary masonry suitable for foundations laid in cement, per perch of 25 feet, at $2 50. Best jointed work laid in like manner (face dressing not included) per perch of like measure $2 85 2 80 3 15 3 00 3 40 Bricks may in many cases be substituted with advantage; if burnt for the purpose, but the ordinary bricks of the country are wholly unfit for any purposes of construction whatever. At Elk creek the ordinary kind will cost In Conneaut valley the ordinary will average The culverts and other small constructions not being greatly affected by these variations, are calculated at the average. According to this mode, small culverts of three, five and seven feet in an embankment of ordinary depth, are estimated for the whole line, at $285, 375, and 480 respectively. Those of 9 feet will cost about Stop gates are estimated in a similar manner Waste gates of masonry (for every opening of eight feet) at Weirs of masonry for a lip of 20 feet Other works however, as the locks and aqueducts, quire a more particular estimation. $610 271 re Locks. These are supposed to be constructed of the most substantial masonry throughout. All the face work, and coping, rough cut, and the bottoms finished with rubble and a good flay pavement or reversed arch of brick. The breast walls should be set above the recesses of the head gates, and the latter constructed in all respects by the same model as those of the tail. to the trunk by means of wooden frames. A 3d, in the same case affords the intermediate support by frames of iron. A 4th, employs a trunk also of iron, and a fifth consists of arches and a complete structure of masonry. The system of construction by means of wooden fratnes, cannot be recommended in any work of this kind of more than ordinary magnitude and expense, and in the situations at Elk and Walnut creeks, where in consequence of the great height, the saving in first cost would be but a very inconsiderable part of the whole, and where for the same reason, any great liability to repairs would be a peculiar evil, they are considered as decidedly objectionable. The same objection, does not apply to the same extent to a wooden trunk, where the supporting system is composed entirely of imperish. able materials, though undoubtedly, the most perfect structure would be that which is built entirely of iron or stone. To the latter material there is one system in the present case on account of the extraordinary expense attending the construction of scaffolding, centres, and other accessary works for turning an arch at so great a height. An iron frame on the contrary, requires no such preparation, it may be set up in the most expedi tious manner, without any centering or extra scaffolding whatever, and becomes immediately the means of completing the remaining parts of the structure. It may be added, that the practical advantages of this mode of construction, are now no longer matter of mere conjecture. One of the finest aqueducts in the world, and in a situation strongly resembling those under consideration, is constructed of iron; and fully confirms after nearly twenty years use, the opinions and calculations of its engineer. Under all these circumstances, my own preference inclines to a structure in which the supporting frames are of cast iron, and the trunk either wood or iron as may be preferred. The system proposed for the A lock of this construction of 10 feet lift, and at the frame, is a little different from that of Mr. Telford, espeErie prices of masonry, will cost $6,530, viz. 1220 perches best masonry, at $2 85 3,447 322 ordinary do. 2.50 5940 square feet face cutting 25 805 90 perches rubble, at $1 50 and 1,680 square feet brick work at 25 555 750 yards excavation (extra) and 180 yards puddle 142 Grillage and sheet piling Gates and all fixtures 125 565 cially if the wooden is used. In that case, the object should be to give two lines of intermediate support to the sleepers of the trunk, and avoid as far as possible, all other strains. For this purpose each rib is made to 5,143 consist of two rafters and a crown beam, having altoge ther, a clear span of sixty-four feet and ten feet rise.The crown beam is entire, spread asunder, on the impost to the distance of 53 feet. The opposite rafters (of 1,387 the same pier but in different arches) are connected across the top of the pier, from head to head, by chains or bars of wrought iron, which will also assist in setting the frames, and the middle of the rafters is supported in a similar manner by a wrought iron tie. Five ribs con $6,530 nected by strainers of cast iron at five points, complete the frame, which is twenty-two feet wide. The strain A similar lock with a lift of 10.41 feet (and supposingers placed at the junction of the rafters and crown beam, half breast walls) according to the prices of masonry at rise somewhat above the rest of the frame with a strong Elk creek, will cost $7,019 50, viz. 1210 perches best masonry at $3 15 3,811 50 339 ordinary do. 2 80 5980 square feet face cutting 15 924 897 flanch upon which the sleepers of the trunk are bolted down in such a manner as to touch the frame in no other point. The trunk is twenty feet wide in the clear at bottom, and 12 at top, the horse path 4 feet wide, -5,632 50 | projecting over the water. The cost of one pier and Section 6. Crossing Walnut creek to the upland on east side 67 perches. Excavation 36,600 yds. for embankment at 12 4,392 00 44,085 00 leaves $297,685; or $6,280 per mile for the cost of all D. B. DOUGLASS, 58,277 00 The following notes and calculations are submitted to the 154 00 Board, relative to the supply af water for the Waterford 1,888 00 summit, and the various questions connected therewith. As the season was rather unfavorable for the operation 64,781 00 of guaging, in consequence of the frequent rains having raised the streams somewhat above their ordinary summer discharge, I adopted the following plan, by conthe influence of the drought of 1826. It will be recolcert with Mr. Ferguson, for obtaining the supply under lected, that in the course of the survey of that year, the waters of French creek were guaged with some care at Meadville, and as it was reasonable to suppose that the ratio of discharge for different seasons was nearly the same at that place and at Waterford, it was now proposed to repeat the measurement there, for the determination of that ratio, at the same time that my measurement was performed at the (2d) forks. Section 7. From Walnut creek to Turkey Hill, near Erie, 7 miles and 262 perches. Very favourable ground except a porous soil as in the former instance, and slight extra cutting at Turkey Hill. Lockage 40 feet. Excavation, viz: 229,350 yards slight profile, including three small feeders 7 cents 18,054 50 Culverts, viz: 3 of 7 feet at $480 and 3 at 3 117,110 embankment and Puddle on 1,920 perches, at $3 50 feet, at 285 Wier of 20 feet lip as formerly estimated Bridges, 9 at $140 and 3 at 250 Grubbing three and one-fourth miles, at $340 and fence seven and three-fourth miles, at 260 dollars 26,594 40 2,295 00 26,120 00 2,010 00 The point selected for the measurement near the forks, was one at which the breadth, depth and velocity of the stream within the line. of the operation continued as nearly uniform as possible, the latter being nearly as could be obtained, the result of mere declivity. Two parallel sections (60 yards apart) and the superficial velocity, were measured in the usual way, the latter by means of thin wooden floats so adjusted as to be immersed in the surface of the fluid. The mean velocity was then deduced in the most careful manner from that of the surface, and the product of this and the mean transverse section evidently gives the quantity of the Section 8. From Turkey Hill to Erie harbour, one discharge. The measured velocity was 1,162 feet per mile and 9 perches, with a lockage of 120 feet. Excavation, viz: 34,415 yards 2,965 00 Dolls. 67,169 40 and ordinary depths, at 7 cts. 3,692 in loose slate at 35 c. 2,409 05 1,292 20 second, the calculated mean- -0,845 feet per second, and the mean transverse section 105,9 square feet; whence the total discharge is obtained at 894 cubic feet per second, very nearly. On the preceding day, the water of Le Boeuff creek had also been guaged and found to afford a supply of 5-6 feet per second, which being also available for the purpose of the summit level, was added to the preceding in estimating the entire supply, the result corresponding to the measurement is 95.1 feet per second. The measurement of Mr. Ferguson was performed at Rodger's ferry in nearly the same manner, except that as the superficial floats were found to be effected by a breeze down stream, another mode was employed for the velocity of submerged floats, which is believed in this case to furnish the more accurate result. The quantity calculated from it is 257. 55 feet per second. It was remarked by Mr. Ferguson, that the creek was falling at the time of the measurement; and in connection with this remark, it should be understood that my measurement was accidentally de89,410 45 ferred till the following morning. The least that could be allowed for the fall in the mean time would be 3-100 part of a foot, which would give 255.4 feet per second for the discharge at Meadville, corresponding (in time) with the gauging at Waterford. 4,916 20 $835,320 63 Or 17,620 per mile. Of this aggregate the crossings of Elk and Walnut creeks, including the embankments and deep cuts, make up 196,084 64-100, which being deducted gives at the rate of 13,481 dollars per mile for the cost of the remaining works. The total expense for lockage at $672 30-100 per foot lift is $341,551; deducting this also, Comparing this with the result of the preceding year (158,9 feet,) and reducing the Waterford supply in the same ratio, we obtain 59 cubic feet per second as the supply of the summit in question under the influence of the drought of 1826, and it is not probable that it will often be found lower than this limit. This it must be allowed is a very moderate supply for the wants of a summit level, but it is not very difficult to adopt a system of lockage to it in the present case in such a manner as to afford in many respects the advantages of a large supply. The mode of proceeding would be as follows: Assuming the length of the summit level, including the feeder, at twelve miles, if we deduct from the whole supply, the quantity due to evaporation, leakage and waste on this distance, say 13 feet per second, we shall This is the third time since the establishment of our have 46 feet per second, as the quantity available for BIOGRAPHICAL NOTICE OF SAMUEL EMLÈN, M. D. the lockage, the half of which234 feet per second, By Charles D. Meigs, M. D. may be drawn off for this purpose at each extremity of the summit level. This we find is sufficient for the From the North American Medical and Surgical Journal, supply of a 10 foot lock, in constant use, and a mile of for July, 1828. evaporation and soakage besides, whence we infer that locks of this lift may be used at the extremities of the his age, SAMUEL EMLEN, Jr. M. D. Secretary of the ColDIED, on the 17th of April, 1828, in the 39th year of Summit level and for a mile down the slope on either side, without any danger of experiencing a deficiency lege of Physicians of Philadelphia, and one of the Phyof water. In proceeding further down the slopes how-sicians to the Pennsylvania Hospital. ever, the surplus of evaporation and soakage will no Journal, that we have been called upon to record the longer suffice for such a lockage, and then it becomes decease of worthy and valuable members of our profesnecessary to determine such a diminution of the lift as sion in this city. EWING was taken from the midst of us shall always bring the demand of the locks within the limits of the supply. On the calculation for this pur. Just at the moment when his talents and virtues had bepose, I assume the entire length of the canal which is gun to render his name familiar to the public ear as a risto be fed from the summit at 34 miles, viz. from Erie to ing and successful physician; the venerable Doctor the nearest point on French creek at which another tion to the humane duties of medicine had crowned him GRIFFITTS, at the close of a long life of successful devofeeder could be taken in. The expenditure of water with reverence and popular respect; and now again, the on this distance for all purposes except lockage would irreproachable EMLEN, having slowly surmounted the be 31 feet per second leaving in round terms 28 feet first difficulties in the way of professional reputation, is, per second still available at the extremes, or 14 feet per by an inscrutable decree of Divine Providence, snatchsecond at each. The locks which would be exactly ed from his family, his friends, and the art, which he graduated to this supply, would have a lift of 63 feet, seemed born to honour and advance by his industry, but as it is not probable that the locks will often be press-abilities, and exemplary life and conversation. ed to their utmost working power, or that the water will be reduced to as low a limit as the one used in these calculations, it will be sufficient to make the extreme locks of 7 feet lift at least, which is better adapted to the ordinary state of the case. Briefly stated then, the mode will be as follows, viz. to make the locks at each end of the summit level, and for a mile down the slope on each side, of 10 feet lift, and afterwards to diminish the lift in a constant ratio per mile, so as to reduce those at the two extremes (of the 34 miles) to 7 feet each, and this will place the whole system in the most advantageous relation to the supply of water. The exact height of the Beaver dam summit level do not know, but it is estimated to range somewhere between 620 and 630 feet (above Lake Erie) after a reasonable depth of cutting. If we assume it at 628 to the top water line, and suppose that five 10 foot locks may be graduated on the first mile of the descent towards Erie, the remainder by the system of diminished lifts will require 68 locks with an average lift of 83 feet. On the Meadville side, the number will probably not exceed two of the 10 feet lift, and about four with diminished lifts to the second feeder, (at the end of the 34 miles) after which about five more will bring the line to Benner's mill. The practical utility of this system will not greatly differ from that of a system of 10 feet locks except that it will require on the part of each boat about 1-6 or 1-7 more time in performing the total lockage of the line; as to the cost, it will be about ten dollars per foot greater. As to the practicability however, so far as the supply of water is concerned, I have no hesitation in giving my opinion in its favor. An apprehension having sometimes been expressed as to the declivity on the Erie side being too great for the lockage, it may be proper to add, that no difficulty will be experienced on this account. It may be in the power of the engineer, indeed, in an extreme case, to construct as many as 17 or 18 locks on a mile, and yet preserve their perfect independence, and this it is presumed is a much more rapid lockage than can be required on any part of the line alluded to. One further remark may also be made in connection with this subject as regards the Conneaut route, viz: that from the smallness of the supply of water, to be obtained from French creek, and the necessary length of the feeder, (which is frequently found more expensive of water than the canal itself, it is not probable that a sufficiency could be commanded on the summit for the supply of a canal by that route. All which is respectfully submitted, D. B. DOUGLASS, Prof. of Eng. ciety, of which he was a valued member and officer, to We have been commanded by the Kappa Lambda SoPrepare a sketch of his life for this number of its Journal; and in obeying this command, we hope that our feelings of personal attachment to him may not lead us overrate his acknowledged abilities. We sincerely deto make any false estimate of his many virtues, or to sire at least to say nothing more than the simple truth in regard to our deceased member. whose lives have been short of half a century, have been Such is the nature of our calling, that few physicians, able to furnish considerable materials for the pen of the biographer. BAGLIVI, SAUNDERS, BICHAT, and some lives are rather to be read in the works they have left as others, furnish rare exceptions to the rule; and even their bequests to posterity, than in the events they witnessed, or the transactions in which they were personally engaged. The peaceful, quiet and unobtrusive tenor of even a good physician's life, affords, for the most part, but litfaithful discharge of duty, charitableness, inflexible intle scope for details, or description; since good sense, tegrity, christian piety, all that renders a man integer degree, without affording very striking features for such vita scelerisque purus, may be possessed in the highest an article. What says the poet? Full many a gem of purest ray serene, The dark unfathom'd caves of ocean bear; And waste its sweetness on the desert air. public virtues as are found to be common and almost trite in times of great political convulsions and revolutions, ought not to be considered as rare or uncommon among men; for multitudes of persons pass their lives in vile trades, or squander their time in humble pursuits, who only require favourable circumstances to enable them to advance science, adorn the arts, or fill the rolls of fame with the history of glorious actions: the same is true of physicians, whose greatness oftener depends on contingencies than on their own pre-eminent qualifications, The occurrence of terrific epidemics, or fortunate appointments to public stations, are frequently the causes which lift men far above their equals in talent or worth. After all it might be asked, what is it that makes men worthy of imitation when living, and of reverence and regret when dead? He only is admirable who begins life with unchangeable resolves to discharge his relative, social, and religious duties, and who in the course of that life, brings constantly up to the mark in performance, what he had aimed at as the prize in promise. The common fault is, that men go on by a sort of rule of chance-medley, have no fixed or predetermined objects or motives, and yielding to the impulse of events, are ever swaying up and down, and come therefore to nothing good. A man may begin with a general resolution that he will lead a moral life; but he is not half so apt to escape the snares of temptation, as he who firmly detertermines to eradicate from his soul the particular seeds of pride, envy, malice, avarice, &c. The very definiteness of the plan ensures its fulfilment. In the death of Dr. EMLEN we have suffered the loss of a man who understood well, and discharged in a high degree, his professional, social, and religious obligations -who had forced his way by sheer merit, without an iota of false pretences or shrewd policy, into the public favour. Dr. EMLEN was born in Chester county, state of Pennsylvania, on the 6th of March, 1789. As springing from one of the oldest and most respectable families of the society of Friends, he received, of course, in his early education, all the advantages which their strict example and sedulous inculcation of good morals could bestow. His education was chiefly English, but as it was carefully superintended, he had in it a solid foundation of knowledge, on which he afterwards erected a considerable structure of various and available information. The flash and gewgaw of education were never very desirable nor pleasing in his eyes, inasmuch as he knew them to be unessentials in managing the solid and stern concerns of life; and herein he conformed to the practice of the religious body of which he was a member, who, though they despise not many of the elegant pursuits of literature, and often combine in a high degree the agreeable with the useful, are more given to the latter than to the former. Dr. EMLEN's acquirements were more solid than specious, and produced in him those excellent fruits which have caused his death to be so much regretted. In the year 1808, having resolved to devote himself to the profession of medicine, he placed himself as house pupil with Dr. PARRISH of this city, and under his roof, and with his example constantly before him, made rapid progress in his studies, to which by the testimony of his teacher, he absolutely devoted himself. Under the roof of Dr. PARRISH, and as a member of his family, Dr. EMLEN passed four years, during which, having attended the lectures delivered in the University by the professors RUSH, WISTAR, BARTON, PHYSICK, JAMES, and COXE, he graduated M. D., and in June, 1812, embarked at New-York for England. Arrived at London in the month of July, he placed himself in the vicinity of one of the great hospitals, where he sedulously endeavoured to acquire the greatest amount of practical and surgical knowledge. Attendance on hospital practice, on lectures by the celebrated individuals whose reputation had attracted him thither, conversation with celebrated men, to the houses of many of whom he had free and familiar access, and visits to ob jects which interest the man of science or the philanthropist, kept his mind on the stretch; and he accumulated a large stock of information, of which he noted down the heads in his journal, which we have perused with great satisfaction, as affording evidence of the diligence with which he employed himself even at that period. The declaration of war by the United States against Great Britain, which reached London soon after his arrival, placed no obstacles in the way of his studies while in the metropolis. The detention it occasioned gave him an opportunity, however, of making an extensive tour through England, Ireland, and Scotland, the history of which is detailed with considerable naivete in his journal. At length the obstacles to his visit to Paris were removed, and after a residence of fourteen months in the island, he reached that city about the time of the emperor's return from Leipsig. His stay in London, and his frequent access to the society of the most eminent physicians, surgeons, and lecturers, had increased his stock of knowledge, while the elegant society in which he moved, although it never abolished the gravity of his carriage, or the serious and sententious style of his conversation, imparted nevertheless to his manners that urbane cast, which is far more estimable and trustworthy than the false and heart, less elegance of mere fashionable intercourse. They were marked by the gentleness, self possession, and confidence which belong to the gentleman. In Paris, though daily attracted by the extraordinary events of that wonderful period of history, Dr. Emlen continued to attend mainly to the objects of his visit.The battles fought in the vicinity filled the hospitals with soldiers suffering under every species of military accidents, which he carefully studied." As we have no events of his history while in France, demanding a particular relation, we need here only state that after the surrender of the French capital he returned to London in June, from whence he proceeded to Holland, and came home in the corvette John Adams as the bearer of despatches to the Government, after an absence of nearly two years and a half. Soon after his arrival he commenced the practice of physic, and was elected one of the physicians to the Philadelphia Dispensary; an excellent school of practice through which most of the eminent practitioners here have passed. In 1819 he resigned this station, in consequence of increasing occupations; soon after which he was elected to be one of the managers, and finally, after the death of his revered friend Dr. Griffitts, became secretary to that charity. During the year 1819, when the yellow fever prevailed along the water margin of the city, Dr. Emlen was secretary to the Board of Health, and made those observations, of which the fruit is to be found in his valuable paper on yellow fever published in the last number of this Journal. As member of the Board of Guardians of the Poor, as physician to the Magdalen Asylum, the Orphan Asylum, and the Friends' Asylum for the Insane, he established broadly and deeply the foundations of a reputation which tended daily to raise him in public esteem. He was an efficient and respected member of the Kappa Lambda Society; and the Journal of that Association is much indebted to him for the usefulness and reputation it has attained. He succeeded Dr. Griffitts as secretary to the College of Physicians, and to his zeal is undoubtedly owing much of the renewed activity and efficiency which marks the present course of that institution. In 1825 he was elected one of the physicians to the Pennsylvania Hospital, an office to which he was annually re-elected, a sufficient proof of the assiduity and ability with which he discharged the functions of that honourable and very responsible situation. This excellent man sat not down contented with the discharge of his merely professional duties. He had ac |