1S42.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



the actual force with which the rim, in falling from a given height, 

 strikes the head of the pile. Obeying the law of accelerated velocity, 



the ram will fall through any space s in the time /k/t, where g=i 



IG^ij feet, the space through which a heavy body falls in one second 

 of time. Now it is a fixed and well established .rule in mechanics, 

 that the velocity acquired by falling through any given height is pro- 

 portionate directly to the time of descent, and that the velocitv ac- 

 quired at the end of the first second of time is equal to 32x feet per 

 second ; hence it follows that the velocity acquired by a body in falling 



through the space « is equal to 32* ./ i. Then to find the force 



of the blow, the weight of the body is to be multipliod into this ac- 

 quired velocity, which it must be understood is not the velocitv with 

 which the body has fallen, but the velocity in feet per second with 

 which it would fall during the next instant of time, were it not sud- 

 denly stopped by striking the pile. 



According to this formula, the following table has been calculated, 

 showing in one column the time of descent in seconds of any ram fall- 

 iug from 1 to 4U feet, and in the other, the force in tons with which a 

 ram weighing one ton will strike, in falling from the same height. 



The force of the blow given by a ram of any other weight than a 

 ton may be ascertained from this table, by simply multiplying the 

 number in the column headed " Force, &c." by the weight of the ram. 

 Thus, if it be required to determine the force of the blow given by a 

 ram of 16 cwt. falling from a height of 30 feet, opposite 30 we find 

 the tabular number 43-9, hence l(i x 43-0 = 702 cwt. = 35 tons 2 cwt. 

 the force required. This is the greatest force of the blow which can 

 be given by the steam pile-driving machine described in our present 

 number, the error formerly made of stating the force of the blow at 

 600 tons was on the authority of one of the foremen superintending 

 the engine, and we take the earliest opportunity of correcting a state- 

 ment so exaggerated. 



The annexed diagram is intended to represent, by means of the curved 

 line///, the law according to which the force of the blow increases 

 with the height from which it falls. For example, the distance a x 

 measured on the horizontal scale will be ti-l tons, the force with 

 which a ram weighing one ton strikes when it has fallen from a height 

 of 2S feet. The peculiar curve here shown is the result of that law 

 by which the forces vary as the square roots of the heights from which 

 the ram falls. If the forces varied directly as the heightji, the straight 

 lines 6 b would express the law of their increase, and if they varied 



as the square of the heights, a supposition which, erroneous as it is, 

 has been entertained by some persons, the law of the forces would be 

 expressed by a curve of an entirely ditferent nature from the true one, 

 namely by the curves c c, according to which, if e i were the force for 

 a height of 5 feet, e e would be the force for a height of 10 feet. The 

 straight lines and the curves c c are of course both erroneous, the true 

 scale for measuring the forces being atTorded by the curved line ///J 

 so that the distance ax of any point x from the vertical line A A, 

 measureu on the horizontal scale S :>, will give the force of the blow 

 correctly in the same manner as the table. 



THE LIVERPOOL PAVILION. 



Ended at Lirerfool, July, 1841, /or tie Great Dinner of the Royal 

 Agricultural Sociily of England, under the direction of I. W. Wiu), 

 JEsj., Architect. 



The object of this dinner is to afford an opportunity to the members 

 of the society, assembled from all parts of the kingdom, of hearing 

 persons eminently connected with agriculture and scientific men, speak 

 upon points of special importance to them. The pavilion requires, 

 therefore, no decoration, as it would for a festive occ.isiou; all that is 

 wanted is that it should be convenient for seeing and hearing the 

 speakers, and for serving the dinner, and that it should cost the So- 

 ciety as little as possible. 



The plan of the Pavilion at Liverpool, as shown in the annexed en- 

 gravings, is a polygon of 24 equal sides, the greatest diameter between 

 the opposite angles being 171 feet; within this space was provided 

 accommodation for 28J0 people, allowing 1ft. Sin. by 3ft. '.Un. to each 

 person, besides the main passages, which were four feet wide, and the 

 committee-room and butteries. The staircases, 3ft. tjin. wide, were 

 outside the building. A portion within this figure being cut oil' to 

 form the ollices, the remaining space for the scats was nearly the form 

 of an ancient circus; the arrangement also was similar, iis there were 

 no galleries, the seats rising in steps around, and following the line of 

 the outer wall. In order to bring the President's and Vice-President's 

 tibles nearer to each other, the high table was advanced from the wall 

 some distance towards the centre of the building, thus leaving some 

 few seats behind the high table. 



There were six entrances into the body of the Pavilion, two upon 

 the ground, leading into the pit, two above these into the upper seals. 



