Page:Sir William Herschel, his life and works (1881).djvu/108

86 "We are told that we gain nothing by magnifying too much. I grant it; but shall never believe I magnify too much till by experience I find that I can see better with a lower power." (1782.)

By 1786, when he returns to this subject, in answer to a formal request to explain his use of high magnifiers, he is quite over any irritation, and treats the subject almost with playfulness:

"Soon after my first essay of using high powers with the Newtonian telescope, I began to doubt whether an opinion which has been entertained by several eminent authors, 'that vision will grow indistinct when the optic pencils are less than the fiftieth part of an inch,' would hold good in all cases. I perceived that according to this criterion I was not entitled to see distinctly with a power of much more than about 320 in a seven-foot telescope of an aperture of six and four-tenths inches, whereas in many experiments I found myself very well pleased with magnifiers which far exceeded such narrow limits. This induced me, as it were, by way of apology to myself for seeing well where I ought to have seen less distinctly, to make a few experiments."

It is needless to say that these experiments