CXXII ROYAL SOCIETY OF CANADA 
“And lastly, some individual plants are naturally earlier than others even 
when in similar localities, and in the same individual certain twigs and 
branches are earlier than others. To check such peculiarities an attempt is 
made to fix the date when the flowering of each species may be said to be 
‘becoming common.’ So that we have the two series of observations for each 
individual, the ‘ first appearance’ and the ‘becoming common.’ 
‘“ Assuming the observers to be symmetrically placed in a country, to be 
competent and careful, and to put exactly the same interpretation on what 
constitutes the ‘first appearance’ and ‘when becoming common,’ the averag- 
ing of the various observations would give us phenological norms for the com- 
parison of a very important character of the country with that of another, 
and more especially for the comparison of one season with another in the same 
country, which after a series of years:would contribute to the solution of the 
problem of the secular variation of climate. 
‘“ In order to deal mathematically with phenological dates, averages or 
means, it is necessary to indicate dates and average or mean dates in terms 
of the day of the year instead of the days of the month. For the conversion 
and reconversion of such dates, all that is necessary to make it convenient, is 
to have before the eye a list of the months of the year with the number of the 
day of the year corresponding to the last day of each month. 
“Now, we may consider a phenological date to be a sort of mathematical 
function of variables, several of which are already being very systematically 
and accurately observed and recorded by the meteorological departments of 
most countries, such as the variations of temperature, of atmospheric pres- 
sure, sunshine, precipitation. Then there are local constants, such as latitude, 
elevation, slope, proximity of bodies of water, and character of the soil. All 
of these influences affect the phenological date, and conversely the date may 
be considered as a summation or integration of all these and other more or 
less unknown elements. We find that in the month of April the season is 
advancing more rapidly this year than last year, while in May or a portion of 
May it may be advancing less rapidly according to the varying balance of the 
meteorological conditions affecting the organisms. Averages of the dates of 
early flowering plants, for instance, during one season might be compared with 
those of another season. Averages of a normally later series of flowers might 
be similarly treated. But to compare one spring with another spring, a series 
of typical flowers normally flowering in succession from the earliest date to 
the latest might be taken. Such an average or mean for comparison we might 
for convenience call a phenological norm or phenochron (a phenological time 
ordinate). Phenochrons for comparison or for the plotting of phenological 
curves should be based on the same number of observations taken at the same 
stations under similar conditions, and if they are to correctly represent any 
district of considerable extent, the stations should be symmetrically 
distributed.”’ 
Returning to the special consideration of the Nova Scotian 
phenochrons following, the province was mapped out into ten meteor- 
ological slopes, basins or “regions,” and each region was, as a rule, 
further subdivided into three “ belts ”— the coast, low inlands, and 
high inlands. The dates in each of these “belts” were averaged to 
