128 
instant, — these together forming a nodal line, both ends of 
which would move simultaneously round the coast as the 
moon passed across the heavens, the wave of high water being 
everywhere the instantaneous expression ot the differential 
force at its nodal point of maximum action. 
By enclosing the continents and land areas which approach 
nearest to the prescribed conditions within one or more 
circles intersecting the salient parts of the coast, the Author 
showed that whenever any systematic progression ot the hour 
of high water could he distinctly traced, that progression is 
almost invariably in the required direction. Owing, however, 
to the irregular shape of all existing land areas, to the im- 
possibility of including some of these in a single circle 
approximating to the coast line, and to the way in which 
some large areas are massed upon others with little or no 
intervening ocean spaces, many instances of anomalous 
results are found; and yet, when rightly considered in 
relation to disturbing causes, even these tend indirectly to 
confirm the method of grouping the data of tidal hours in 
relation to land areas as causal centres. 
A Paper was read “ On the number of Days on which 
Rain falls annually in London, from observations made 
during the 56 years, 1807 — 1862.” By G. V. Vernon, 
F.R.A.S., M.B.M.S. 
This paper has been compiled to meet, to some extent, 
inquiries which have from time to time been made to me by 
medical men and others as to the number of days on which 
rain falls annually at any station. Of course, the remarks 
only apply to London and its immediate neighbourhood. 
Howard's Climate of London , has been used for the years 
1807 to 1831, Philosophical Transactions for the years 1832 
to 1840, and the Greenwich Observations for the years 1841 
to 1862. During the entire period of 56 years no month 
occurred in which rain did not fall. 
