As an applied mathematician (and for some years at Cambridge a co-worker with Sir Geoffrey Taylor in the field of turbulent flow), he was a keen advocate of the need for physical understanding and sound experimental basis.
His An Introduction to Fluid Dynamics (CUP, 1967) is still considered a classic of the subject, and has been re-issued in the Cambridge Mathematical Library following strong current demand [1]. Unusual for an 'elementary' textbook of that era, it presented a treatment in which the properties of a real viscous fluid were fully emphasised.
References
^ G. K. Batchelor (2000). An Introduction to Fluid Dynamics. Cambridge Mathematical Library series, Cambridge University Press. ISBN 0-521-66396-2.