Jim Henderson wrote:  
> I'm trying to pinpoint the month that the first edition (1798) of   
> Malthus's "Essay on the Principle of Population" appeared in public.  The   
> "Preface" is dated "7 June 1798".  
  
  
I am not sure that we can pin it down, but we can discover a terminus ad   
quem from the letter of E. D. Clarke to Malthus in vol. I of the Kanto   
Gakuen collection. The letter is dated 20 August 1798 (which was a Monday)   
and was written from Northampton. It describes in great detail an animated   
dinner-table conversation in Cambridge between Clarke and three other dons   
about the theologyof the first Essay which took place some time the previous   
week. So the Essay must have been in print long enough, by 20 August, for it   
to have been read by at least some of Malthus's prospective audience.  My   
guess is that it came out some time in July 1798.  
  
Anthony Waterman