356 PROFESSOR FORBES ON THE CLIMATE OF EDINBURGH. 
in two groups of three, each give constant factors of the meteorological elements 
so extravagantly wide of one another as not to be worth reporting. 
78. It may of course be said that the meteorological data affecting the 
harvest are mainly confined to one critical period of the year. It is also true 
that extremes, whether of heat or cold, drought or wet, are not favourable to 
abundant harvests.* Making all allowances, however, the results are exceed- 
ingly anomalous, and seem to show that the price of corn cannot be used to 
afford the slightest clue to the temperature or meteorological character of a given 
season. 

Postscript. 
I have already acknowledged the assistance which I have derived from Mr 
Grassick, and especially from Mr Batrour Stewart, in the preparation of this 
paper. I have farther to add, that Iam indebted to Mr Stewart for the pro- 
jection of the curves of Plates XVIII. and XIX., and to Mr Rosert Cram for the 
calculation of several of the Tables. 
* The same remark is made in page 39 of Mr Jenyns’ “‘ Observations on Meteorology,” a very 
carefully compiled work. It might be possible to include this view of the case by considering the 
prices to vary with the square of the departures of the meteorological elements from a certain 
amount most favourable to cultivation, but I find no encouragement to make a fresh calculation on 
this more complex system, 

