Note H — Front matter
Reading edition
For a full discussion of these topics, see paper by Professor B. C. Jillson, Transactions of the Academy of Science and Art of Pittsburg, December 8, 1893; G. F. Wright, American Journal of Science, vol. xlvii, pp. 161-187; especially pp. 177, 178; The Popular Science Monthly, vol. xlv, pp. 184-198.