Sir,—We wish to acknowledge the generous assistance of Maynooth University in the person of Niall McKeith, who facilitated the preparation and writing of our article on Nicholas Callan (HI 30.1, Jan./Feb. 2022). We are especially grateful for his provision of an image of the ‘Maynooth Battery’ (p. 24) and for relevant literature.—Yours etc.,
BRIAN HOPKINS & PETER McCLINTOCK