402 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[OCTOBBR, 



diminished ; and at the Season of periodical floods, huge masses, weighing 

 forty tons and upwards, would be precipitated to the bottom. This was the 

 state of the great fragments at the bottom of the ravine, all of them bearing 

 evidence of having been dislocated by the power of the water exercised upon 

 the pot-holes. Such was the method by which tliis gorge, several miles loug 

 and about COO feet in depth, had been ground out of this mountain of gneiss. 

 At this locality were the evidences of the volume of the river having once 

 been at least ten times larger than at present. A semi-circular ledge of 

 gneiss, at the top, east of the stream, and 1,200 feet wide, was worn bare for 

 a great distance, and down its perpendicular face was concave, as if the river 

 had been projected over the top, and the screen of water inface of the concavity, 

 and the concussion, and the moisture, had produced the usual eflect, of peel- 

 ing off the coats of the rock. It presented much such an appearance as the 

 rock at the Horse-Shoe Fall at Niagara would do, if the water were to be so 

 much diminished at tliat point as to abandon it, and to be projected only 

 from the comparatively small fall of the Schlossa, on the American side of 

 the river. For the other example of the snhtrnclhuj, or undermining power 

 exercised in the recession of cataracts, the Falls of Niagara were taken, of 

 which a flat view was given, together with a section of the rocks. Mr. Fea- 

 therstonhaugh had published a paper, in 1831, explaining the recession of 

 this cataract. It is well known that the river Niagara flows upon a bed of 

 limestone from which it projects itself, and that this rock is supported l)y a 

 strong bed of friable shale upwards of seventy feet thick. The moisture 

 arising from the screen of water, the current of wind behind it, and the con- 

 cussion, loosen and remove the shale, and the superincumbent limestone, 

 losing its support falls down. In this manner the cataract has receded at 

 least six miles from the Queenston heights. Mr. Featherstonhaugh expressed 

 an opinion that tliis operation of excavating long channels of rivers, as in the 

 instance especially of the Mississippi, may be considered in the class of pro- 

 vidential aTrangemcnts, since by it the lakes, swamps, and immense mereea- 

 geous surfaces become drained, and rendered salubrious and productive habi- 

 tations for man. There were many other interesting points brought forward 

 in this paper, of which we have only room for this abstract. 



Observations on Subterranean Temperature in Irelanc. 



In July 1843 thermometers were placed at the copper mines of Knnck- 

 matson Company, Waterford, which are worked to the depth of 774 feet. 

 Of the four instruments employed, one was hung in the open air four feet 

 from the surface ; one hung freely in the gallery at the depth of 774 feet; 

 one in the rock at the same depth ; and one in the lode or metallic vein. 

 The rock is indurated clay slate, the ore massive copper pyrites in quartz 

 veinstone. The average of all the readings of these thermometers during 

 eleven months was as follows : — 



Thermometer at the 

 Depth of 774 feet. 

 At the Surface. Air. Rock. Lode. 



Average 50'026 57-176 57-369 57-915 



Maximum 58-25 58-5 58-5 



Minimum 56- 56-5 



Taking the average temperature in the rock as the mean at that depth, and 

 allowing 100 feet for the depth to which the action of solar causes may ex- 

 tend, or to the line of no variation, there is an increase of 7343 for the 

 depth of 674 feet, equivalent (o 1" in 91-82 feet, a rate of increase about one 

 half as rapid as the rate deduced from a large number of observations in 

 England, which gave an increase of 1" in 45 to 50 feet. Mr. Oldham also 

 noticed the fact, that there was a gradual decrease in the actual tempera- 

 ture, during these observations : the average of the thermometer in the rock 

 being 57-718 during the first half of the observation, and 57-004 during the 

 latter half, being a decrease of -674 during the eleven months, although more 

 men were employed, and the works more extensive than at the commence- 

 ment. 



on the causes of the great VERSAILLES RAILWAY ACCIDENT. 



By Mr. J. Gray resident engineer to the Hull and Selby Railway. 

 This paper commenced by observing that having seen the name of a near 

 relative published as among one of the sufferers, he immediately set ofl" for 

 Paris, and that whilst there he endeavoured to possess himself of all the in- 

 formation which might in any way bear upon the occurrence. Having traced 

 the order in which the train left Versailles for Paris, he proceeds to inquire 

 into the cause of the fire which followed the overthrow of the train. This 

 he attributes to the fact of the fire of dne engine being scattered about and 

 coming in contact with the carriages behind, and especially the combustible 

 matter contained therein. He then goes on to describe the cause of the ac- 

 cident which he traces to the breakage of an axletree first at the one and 

 afterwards at the other end. He says, from various facts and circum- 

 stances connected with the great accident of the 8th May, J842, on the 

 Paris and Versailles Railway, it was shown, step by step, that nothing 

 but a failure in the front axle of the engine could have been the first cause 

 of her right hand wheel slipping within the rail. Following this he gives 

 a series of observations on tlie axle, with remarks and illustrations of the 

 importance of uniform elasticity or vibration in the preservation of all 

 articles subjected to sudden strains or percussive forces. He says, in 

 conclusion, with good materials and proportions and the axles in a state 

 of repose as received from the forge, or, in other words, perfectly free 

 from the effects of cold swaging or hammer hardening, an axle in such 



a state, and of ample dimensions for its intended work, will, I have no 

 doubt, most effectually resist fracture, for any period the wear of the jour- 

 neys may enable it to run. But, if the dimensions be deficient, the iron will 

 be taxed beyond its permanent cohesive power and elasticity ; and, however 

 slight the excess of exertion and fatigue may be, a gradual and inevitable 

 dissolution of particles must result ; but beyond this I have not met with 

 anything, «ither in print, in observation, or in the course of experience, that 

 would at all warrant my belief in iron necessarily changing its quality, or he- 

 coming crystallized by forces within the range of its permanent cohesive force 

 and elasticitv. 



On Steam Navigation in America. — By Ur. Scoreshy. 

 After alluding to steam navigation as having an important bearing upon 

 the national prosperity and the development and employment of the national 

 resources of America, equal to that of the steam engine upon the national 

 wealth and commercial greatness of our own country, the author proceeded 

 to notice the extent of navigable waters in North America, which he said, 

 including the coast lines and the waters of the British possession, might be 

 roughly estimated at 25,000 to 30,000 miles ; for such was the vast extent 

 even now traversed by steam-boats, partly coastways, but mainly inland in 

 the United States alone, that the summing-up of the steam-boat routes given 

 in a guide book not of the most modern date, made a total distance, omitting 

 repetitions of the same track, of 13,444 miles. In enumerating the various 

 waters, and particularly in reference to the Mississippi, he observed that none 

 but steam-boats liad any or little chance of making way, from the rapidity of 

 tlie current, the average of which in Ihe Mississippi was four miles an hour. 

 The author went on to allude to the introduction of the steam-boat by Mr. 

 Fulton, in 1807, and the rapid progress that had been made, and then directed 

 the attention of the section to the peculiarities of some of the boats, namely, 

 the general attention to elegance in the style of fitting up, the construction 

 of the cabins on deck, and the application of the hull of the vessel entirely to 

 cargo, the working of the rudder at the forepart of the vessel by means of 

 communicating rods, the use of a distinct boiler and machinery to each pad- 

 dle, &c. With regard to the speed he observed that it was much beyond 

 that of our steam-boats, from the circumstance of the Americans adopting 

 the high pressure principle, and that too to an extent at which the generality 

 of Englishmen would be loth to trust themselves. Whilst our boats were 

 worked at a pressure of 5 lb. to the square inch, tliey thought nothing of 

 1001b. or 1501b. pressure; and, in addition to loading the valve, the engi- 

 neers had been known to sit upon it in order to gain increased speed. The 

 most extraordinary performance of American steamers was eft'ected by the 

 " J. M. Whitp.," in the summer, of this year. She made her way against an 

 average current of from 3 to 4 miles an hour, from New Orleans to St. 

 Louis, a distance of 1200 miles, in three days and 23 hours, remaining a day 

 and a half at St. Louis, unloading and loading, and reached New Orleans 

 again, having performed a distance of 2300 to 2400 miles in little more than 

 nine days. The average speed, taking certain advantages and disadvantages, 

 into consideration, would be 16 miles, or perhaps near 14 knots per hour. With 

 regard to the dangerous character of the western boats (improved now, but 

 far from safe,) the author observed that in 1834 an American paper stated 

 that 1500 persons had lost their lives in American steam-boats, by the burst- 

 ing of boilers, during three years, and that in two years, from 1832 to 1834, 

 67 steam-boats were lost or abandoned in the western waters. 



A Micrometer. 

 Mr. Whitworth exhibited a machine for ascertaining the diameter of 

 metallic cylinders or gaugeis, with an extreme degree of accuracy, amounting 

 to the ten thousandth part of an inch. The gauges or cylinders are to be 

 used as standards of size, where practicable, instead of the two-feet rule. 

 The truth of the machine depends upon the perfect accuracy of the screw. 

 The object to be measured is passed by the hand between two surfaces, which 

 are actuated by the screw, and a difference indicated by one division of a 

 wheel, on the screw, amounting to the ten thousandth part of an inch, is 

 distinctly sensible to the hand. This occasioned considerable surprise, that 

 a difference in size so extremely minute shoidd (by touch) be distinguished. 

 The thickness of a hair was taken, and found to be 0019 decimal parts of an 

 inch, and the thickness of a piece of tissue paper 0017 decimal parts of an 

 inch. 



Grenier Mobile, or Moveable Granary for Preserving Corn. 



Professor Byrne explained the nature of this invention, it was the result 

 of the ingenuity of the French, and they were introduced here in order that 

 the intelligence of the EngUsh, if they thought them practicable, might be 

 brought to bear upon them in the way of improvement. The machine con- 

 sists of a cylinder, divided into compartments, which will hold SOO quarters 

 of corn. It is made of zinc or galvanised iron, and turns round like a barrel, 

 so that the grain is thus turned over by one man daily. The advantages are 

 that the corn gets gradually dried, may he preserved for a longer period, bad 

 corn is improved, grain generally comes out heavier than when it went in, 

 and it is not bruised and wasted by being turned over with the shovel. With 

 regard to the increase (?) in weight, it was stated at 6j lb. in 110 cwt. The 

 cost of the machine is about 1/. a quarter. — Mr. Bermingham supposed that 

 a person expended 100^. on one of these machines, which would hold 100 

 quarters of grain ; the interest of the 100/. would be, say 5 or 6 per cent., 



