(written on letterhead:
 First Congregational Church
 Burlington, Vermont
 Rev. Joel H. Metcalf, Pastor)
 
 

Prof. J. M. (W?) Scharberle (sp?)

Dear Sir:

 I am interested in grinding lenses and have read with pleasure what you have written on the subject in the Popular Astronomy.

 Knowing that you have spent much time in this direction I take the liberty of asking you a few questions.

 1st. Does the Pub. of Astron. Society of the Pacific No.42. + 44. Contain an account of the details of grinding your mirror.
If so where can I apply to get the numbers.

 2= Is there anything written which shows the modification of the curve of a lens by the change of motion in grinding.
That is what kind of motion ought to produce a spherical parabolic xc (+e? or ?).

 3= Can you tell me in a few words what the effect of a change of amplitude of motion is where the tool and lenses are both the same size.

 My trouble is that my lenses come out short formed on the middle and I am not sure what the cause is. My spherical aberaton (aberration) is always over corrected. (a Refractor)

 I am sorry to trouble you but any hints you might give me would be very gratefully received. And if you know any literature on the subject that I could obtain a reference to it would be very acceptable.
 

       Yours Truly-
               Joel H. Metcalf