Sir

Altho’ unknown to you I take the liberty, with reference to your book on earthworms,¹ of drawing your attention to the stacks of heavy cannonballs which in many forts are often remaining on the ramparts undisturbed for years and the considerable sinking of which into the soil has long been a puzzle to me.

The matter has been revived in my mind by your intensely interesting book, which at the time of a recent visit of mine at Woolwich Arsenal I unfortunately had not yet read.²

I remember however having noticed there a considerable number of shell- and ball-heaps, and I mention this fact thinking that an inspection of these would perhaps occasionally not be very inconvenient for you, as the distance from your house cannot be considerable.

Hoping you may not consider this note as an unwarranted intrusion | I remain Sir | your true admirer | Heinrich Simon.

Charles Darwin Esq | Down