224 Herschei/s Observations of the Transit of Mercury 
Confined Place. 
(42.) July 19, 1781. 13 11 15'. My telescope would not act 
well ; and, supposing the exhalations from the grass in my garden 
to affect vision, I carried the telescope into the street, (the ob- 
servation was made at Bath,) and found it to perform to 
admiration. 
(43.) July 19, 1781. My telescope acted very well; but a 
slight field-breeze springing up, and brushing through the street 
where my instrument was placed, it would no longer bear a 
magnifying power of 460. 
Haziness and Clouds. 
(44.) Sept. 22, 1783. The weather is now so hazy, that the 
double star $ Cygni is but barely visible to the naked eye. This 
has taken off the rays of the large star, so that I now see the 
small one extremely well, which at other times it is so difficult 
to perceive, even with a magnifying power of 932. 
(45.) August 13, 1781. A cloud coming on very gradually 
upon fixed stars, has this remarkable effect, that their apparent 
diameters diminish gradually to nothing. 
(46.) July 7, 1780. The air was very hazy, but extremely 
calm. I had Arcturus in the field of view of the telescope, and, 
the haziness increasing, it had a very beautiful effect on the ap- 
parent diameter of this star. For, supposing the first of the 
points, Plate III. Fig. 1, to represent its magnitude when bright- 
est, I saw it gradually decrease, and assume, with equal dis- 
tinctness, the form of all the succeeding points, from No. 1 to 
No. 10, in the order of the numbers placed over them. The last 
magnitude I saw it under, could certainly not exceed two- 
