186 Some Account of the Solar Spots which appeared in 1816. 



It may be concluded, therefore, from the foregoing statement^ 

 that the spots on the sun could have had no effect in producing 

 the inclement summer and autumn of 1816, for these reasons: 

 first, because no spots appeared upon the disk of sufficient mag- 

 nitude to intercept any material portion of light ; and conse- 

 quently the atmosphere could not have been influenced hy such 

 a circumstance. Secondly, that although numerous spots may 

 have existed, their duration was always too short to produce any 

 permanent or great effect; and therefore it is unreasonable to 

 suppose the atmosphere could have been afl'ected by such trans- 

 itory appearances. Thh-dly, it must be remembered that if any 

 extraordinary influence can be conceived to result from the solar 

 maculae, it would not be confined to one quarter of the world 

 rather than another; since the diurnal rotation of the earth 

 would, in succession, expose all climates and countries to the 

 same privation*. 



feb. 1, 1817. 



*It may not be improper to state, that the above observations were 

 made "ith a tlircc-feet-and-half achromatic telescope, to tl e end of '.vliich 

 was adapted a lii;'it frame restmbhiig a three-leiiged stool. This fiaaie 

 was fixed upon the telescope by means of a hole tlirouj;h which the smaller 

 end of it was accurately fitted, being lined \iitli cloth tlmt it inii;hr be made 

 firm,' without injury to the telescope. The legs of the frame expand, and 

 at the <Mstance of seven or eight inches a tbin circular board was (ixcd to the 

 ends of thcni parallel with the eye-fjass of the telescope. Upon this board 

 a paper was placed, havins; a circle drawn on it of the same diameter as 

 that produced by the image of the sun's rays falling upon the board witii 

 the focus of the eye-glass properly adjusted. Across tiie circle were 

 drawn three lines ; one exactly perpendicidar to the horizon; another in- 

 clining eiuht degrees westward, representing the axis of the sun; and a 

 third at riuht auijles to the axis representing the equator. When the ap- 

 paratus was used, the window-shutter was closed, except one lold ; and 

 over that was placed a thick piece of cloth, having a hole in the middle 

 with a kind of sleeve inserted into it. The telescope was passed through 

 this sleeve, which reeved up close round the tube with a string, and the end 

 then put out at the window and directed to the sun. Wlieii the image was 

 perceived on the paper, a small weight suspended by a hue silk thread af- 

 fixed to the upper leg of the frame, threw a shadow across th.e centre of 

 the disk, and the perpendicular line d.iawn on the paper was then made 

 exactly to correspond with it. Thus prepared, the situation and size of 

 any spots might be marked on the paper with a pencil; and l)y accurately 

 adjusting the shadow of the silk to the vertical Ime on the paper in suc- 

 cessive observations the motion of the 5|)0ts n>ay be traced with accuracy. 

 It is necessary, however, in making observai:ons of some continuance, 

 where several spots are to be marked, that an assistant should carefully 

 turn the rackwork to correspond with the motion of the sun, oilierwise the 

 disk and the circle on the paper will not coincide, A little practice ren- 

 ders this easy. 



Messrs. W. and S. Jones, opticians in Holborn, are acquainted with the 

 apparatus used by the writer, which may be adapted to any achromatic 

 telescope ; and gentlemen, and even young ladies, may be enabled to 

 amuse theriiselves with observing the solar pha;nomena, without trouble 

 or ditfuulty, and also without hurting their cyts. 



