164 PROCEEDINGS OF THE [July, 1887. 



data are far less precise, the remaining five cases will give an average velocity of 

 projection of 10 ft. per second, and an average direction very nearly north. 

 These results unj^ly impulses from points varjaug from S. 23° E. to S. 15° W., 

 with an average direction from south. With these five cases may be associated 

 No. 43, which indicates jDretty clearly an impulse from a point S. 10° E. The 

 six cases here mentioned range from St. jVIichael's Cametery to Magnoha Cem- 

 etery and so far tend to give an average result for the portion examined ( about 

 3 miles in lengih ) of the strip of land between the two rivers. 



Two cases, Nos. 9 and 14, both in St. Philip's Cemetery, give each a velocity 

 of 6 ft. per second with directions, E.in first case, E. 5° S. in the second, show- 

 ing an impulse from the west. 



In one case. No. 19, the fallen mass was found S. 20° W. of its piUar, indica- 

 ting an impulse from the opposite point of the horizon. But it lay so near its 

 pedestal, that it may perhaps be equally probable that it was but weakly attached, 

 was broken off by its own inertia, and so fell behind, under an impulse from S. 

 20^ W., and so it might be associated mth the first six. 



If in the preceding cases, the dhection of the impulse be supposed, not hori- 

 zontal but obliquely upward, then the velocities of projection will respectively 

 be greater than those given above ; but we have found no means of determin- 

 ing the angle of this obhquity. 



We may next examine the direction of falls of obelisks and columns from 

 their pedestals and theh motions on their pedestals, without falling, accompa- 

 nied or not by rotation about a vertical line ; bat here our success will be 

 small. The amount of adhesion or of friction between the lower sm-f ace of pillar, 

 and upper surface of pedestal is unknowTi and also varies in different cases ; in 

 some cases, the two surfaces are comparatively smooth, in other cases, a bed of 

 plaster of Paris, or a sheet of lead is interposed between two roughened surfaces. 

 Opposite rotations may be observed in obelisks within a few yards of each 

 other. The conclusions that may be drawn from the present class of facts 

 agree, in the main, with that drawn from the former, namely that the impulses 

 came from some southerly quarter ; but there are clear indications that some 

 impulses came from an easterly dhection, some from a westerly, and some even 

 from a northerly direction, of which last the Statue on the Orphan House may 

 be taken as an example. Some of these cases may be referred to a vibratory 

 motion, ending in the overthrow of the columns, some in one dhection others 

 in opposite directions ; but this will requhe a particular relation between the 

 periods of oscillation of the earth, and of the column, which cannot be shown, 

 or may not exist. These varied directions of faU were exhibited by columns 

 within a few hundreds or even dozens of yards of each other, in the Cemetery 

 of St. Philip's, and the adjoining one of the Circular Church. Some portions of 

 the strip of land between our two rivers, seem to have trembled as if each of such 

 portions was a jelly-like mass, changing the direction of the motion of its parts, 

 under the varying strains produced in its internal structure. In many cases of 

 rotation the base of the obelisk, was not only rotated about one of its angles as 

 Gray's mode of explanation requires, but this angle was also displaced from its 

 seat on the pedestal. When this displacement was small we may suppose the 



