Our usual laboratory hours are 8.30 to 5.30. On rare occasions that time may be somewhat extended...As a rule I think it is not well to work too long in the laboratory. Some reading and thinking must be done. Our chemical laboratory [sic] is open in the evening for reading.

Letter to J. B. Dickson, 2 April 1915. Quoted in Sheldon J. Kopperl, 'T. W. Richards' Role in American Graduate Education in Chemistry', Ambix, 1976