June 20, 1878] 



NATURE 



195 



end of a lane (Northbrook) leading to some fields, the hedge on 

 the right for some yards was lying in the road, but the field 

 beyond at this point presented only the appearance of an ordi- 

 nary storm, while the lane itself was like the bed of a river. To 

 the left was a field of standing grass ; for about twelve feet from 

 the hedge the grass remained intact, then for about the same 

 distance it was as though it had been mown down. This 

 torrent, for such it might have been compared to, came to almost 

 a £udden termination a little above the end of the lane, but it 

 extended down the Hill till it was joined by two others, one of 

 which had carried a hedge away bodily. 



The increased volume of w ater then poured down over some 

 gardens, uprooting trees and vegetables ; in less than ten minutes 

 the hedges were lost sight of, and the water rose to a height of 

 eight feet. This was occasioned by a block caused by an arch, 

 which carried off the water from a small stream, not being large 

 enough to take the increased volume. Finally it burst over, 

 scooping the ground out in front of some cottages several feet 

 deep and flowed on as a river some yards wide, again destroying 

 gardens in which were valuable stocks of vegetables. 



Near this point the volume of water was again increased ; in 

 all five distinct water-courses could be made out, all of which 

 had done considerable damage to grass, cornfield^, and gardens. 

 Finally, all united in one body and poured into the village of 

 Weston, levelling three walls as it came, and thence passed into 

 the river Avon. 



I gather from spectators at Kelston Hill that it began to be 

 cloudy at half-past four in the afternoon ; at five there was a 

 rattling clap of thunder, followed by a downpour of rain — in 

 "bucket-fulls," as one expressed it; but all seemed to agree 



that the greater portion of the water fell under the brow of the 

 hill, where it came down in several columns. There were no 

 houses close to the spot ; had there been they must have been 

 washed away. 



The atmosphere had been perfectly still all day, but very 

 sultry. Heavy rain fell in the neighbourhood, and the storm to 

 which I have referred specially was accompanied with hail, 

 which in a few minutes covered the ground some inches deep. 



What I have described is no doubt what is popularly termetl 

 a waterspout. 



The damage done was at first estimated at 2,oco/., but it is. 

 now feared that this amount will not cover it. 



Weston, near Bath, June 17 E. Wethered 



Fortunate "Escape" 

 An evening paper of to-day's date has the following : — 

 "house struck by lightning. 



" During the thunderstorm yesterday, at about 2.30 p.m., a 

 large stack of chimneys at the residence of Mr. Robert Avis, at 

 Putney, was stnick by lightning, which split the chimney-shaft 

 down the whole height, the electric current passing down the 

 chimney and into a sitting-room on the ground floor. Tke dcor 

 of the room was fortunately open, and the current escaped tinthout 

 causing injury to the family, who were in the room at the time of 

 the shock." 



The italics are those of one Electrified 



June 17 



Velocity of Light 



^yILL ycu have the kindness to publish the following as a 

 preliminary announcement : — 



The following method of measuring the velocity of light 



dispenses with Foucault's concave reflector, and permits the use 

 of any distance. 



In the figure, j is a division of a scale ruled on glass ; m, a . 

 revolving mirror, /, an achromatic lens ; /', a fixed plane mirror' 

 at any distance from /. 



The point j is so situated that its image s reflected in the 

 mirror m is in one of the foci of the lens /, while the image of 

 s' coincides at /' with the mirror, the latter being placed at the 

 conjugate focus. With this arrangement, when m turns slowly, 

 the light from /' is reflected back through the lens, so that an 

 image is formed which coincides with s. When, however, the 

 mirror rotates rapidly, the position of m will have changed while 

 the light travels from m to /', and back again, so that the image 

 is displaced from s in the direction of rotation of the mirror. 



Let Fbe the velocity of light ; D, twice the distance m s' ; n. 



the number of turns per second, and r the distance vi s ; then, 

 calling 5 the deflection, Vis found from the formula — 



rr _ ^Tf rn D 

 5 



In a preliminary experiment the deflection amounted to five 

 millimetres when the mirror revolved 128 times per second. 



The following is another plan which would probably giye*^ 

 more light than the above. - .'., 



s is as before the image of the scale reflected in tb^ mirror JfWj^J^ 



its image would be formed at i" by the lens /, and the image 

 of y would be formed at /", where the plane mirror is placed. 

 In this case also, the rays are reflected back, so that the scale 



and its image coincide notwithstanding the (slow) rotation; 

 of m. Albert A. Michelson 



U.S. Naval Academy, Annapolis, Mar}- land 



University College 



The fiftieth anniversary of the opening of University College 

 falls within this year. It is intended to celebrate the occasion by 

 a gathering of members of the corporation, present and past, 

 professors and masters, old students of the college and school, 

 and other friends and benefactors of the institution, to be 

 held within the precincts of the college, on Tuesday, July 9, at 

 I o'clock P.M. The Right Hon. Earl Granville, K.G., Chancel- 

 cr of the University of London, has kindly accepted the invita- 



tion of the President, Council, and Senate to attend and lay the 

 first stone of a further extension of the college buildings and 

 preside at the luncheon ; and the presence is expected of many 

 other persons of distinction interested in the welfare of the col- 

 lege and in the promotion of University education. 



The space at the disposal of the coUege, even since the school 

 has been entirely withdrawn to the south wing, is far from ade- 

 quate to the rapidly increasing requirements of modern educa- 

 tion. The Fine Art Department has been obliged to refuse 

 pupils. The Council ha--, moreover, after prolonged experience 



