HORIZONTAL MOON, 109 



Tn his firft experiment, «« from the flame to the lens the dif- Exp. i. The 

 tance was 49| inches, and from the lens to the image il was ° e ir t he leasT 

 SS inches." Theft: numbers being reduced to the fcale of the 

 human eye, it will appear that the diftance between the cry- 

 ftalline lens and the retina, is nearly twice as great as be- 

 tween the cryfialline lens and the object ; confequently, if we 

 take the diftance between the crystalline and the outward fur- 

 face of the cornea into the calculation, the object mud nearly 

 touch the eye. This, I think, may be called a Jliort-Jighted 

 experiment. 



The conclufion of C. L.'s paper contains a number of par- 

 ticulars, in which he fuppofes I have erred, and then modeftly 

 '* fubmits it to yourfelf and readers, whether I have acted con- 

 fidently with the rules of philofophical investigation," &c. 



But as it will appear hereafter, that none of thofe errors had 

 any exiftence, except in C. L.'s own mind, his conclufion can 

 ferve no other purpofe than to fliew the temper and difpofition 

 of the writer. 



In my paper which was honoured with a place in the 9th A more partlca- 

 vol. of 'this Journal, page I 64-, I only gave an abftrad of a ^^rVL- 

 feries of experiments, on which I founded my general con- mer experiments, 

 cluflon ; but it now appears neceirary to give a more particular 

 account of them, to (hew that they are entitled to more credit 

 than C. L. has thought fit to give them. 



After having prepared my apparatus as defcribed in my 

 paper above-mentioned, with a long mould candle of fix to 

 the pound, placed in an inclined pofition, I began with mea- 

 suring the focal image of the whole lens. 



The length of this luminous picture upon the fcreen, was 

 determined by a pair of compaffes, and a diagonal fcale of 

 inches. This meafure was entered on page 1 of a book, pre- 

 pared for that purpofe. 



The card No. 1. was then placed before the lens; the 

 luminous picture meafured in the fame manner as before, was 

 entered on page 2 of the fame book. 



The meafure of the picture given by the aperture, No. 2. 

 was entered on the 3d page. And the meafure of that given 

 by No. 3. was noted do vn on the 4th page. 



As foon as thefe four experiments were finifhed, I began 

 again with the whole lens, and entered a fecond meafure on 

 page 1. under the firft, and continued l\\\ I had obtained two 



meafures 



