I SHOULD fancy from the review by “G. H. B.” in NATURE of July 19 (p. 265) that the papers of Prof. Levi Civita relate largely to the mixed transformation of Lagrange's equations, the complete theory ...

PROF. ORR'S opening remarks perhaps indicate that the want of appreciation of Newton's dynamics is even greater than I supposed. My authority for Newton is that stiff but thorough-going work, Thomson ...