ALL CORRESPONDENCE 
SHOULD PE ADDRESSED 
TO THE SECRETARY 
S. P. LANG LEY. 
Smithsonian Institution 
Washington, D. C. 
April / / , 1902. 
Dear Mr. Holmes: 
I Have frequently spoken to you of my personal 
interest in tine oases illustrating the history or the evolu- 
ti on of measurements, both in space and time - or rather, 
rlilWCT*.*'. a, .VfrVMVi. I IV 
I should say, the evolution of the idea in the human mind, 
that such things are measurable quantities, - and I have been 
speaking to Mr. Maynard about my hope that this thing, which 
I in it iate&jbut to which I can no longer give my personal 
attention, should not be wholly discontinued* 
My idea would be that in illustrating measurements 
of space, the case should contain the most archaic instru- 
ments, such as might be found among some primitive tribe, for 
determinations of length, of quantity, and of weight ; and 
pass from this through secular periods of development down to 
the most recent Ruprecht balance, the most complete dividing 
engine, the most perfect measurement of cubic capacity; 
these latter possibly connected with the refinements of the 
latest exposition of the metric system* 
Regarding tine, you will remember, I had hoped to pass 
in fcne same way x rom the stick which the savage places in 
