56 
Proceedings of the Royal Soeiety 
intensity of tlie band. The fourth line, which could scarcely he 
represented by an ordinary curve, illustrates the visibility of the 
thin lines in the green on the scale — 
Invisible, Indistinct, Pretty distinct. Distinct, 
but for reasons already stated this curve is less reliable than the 
others. 
Summing up the results, it is seen that on sixteen days the predic- 
tion was that more or less rain would fall, and that this was verified on 
fourteen, or 87 per. cent. “ JSTo rain ” was anticipated on the remain- 
ing fifteen days, and on twelve of them, or 80 per cent., there was 
no rain. The mean percentage of successful forecasts (83*5) is not 
altered by omitting those days on which only slight showers occurred. 
The 11th and 19th are the most marked instances of erroneous pre- 
diction shown on the chart. It is interesting to notice the general 
closeness with which the rainband curve follows that of temperature. 
This is strikingly shown for maxima on the 1st, 17th, and 24th, and 
for minima on the 4th, 8th, 26th, and 31st When the divergence 
of the curves is considerable the nature of the weather to follow is 
always decided. Thus, when the thermometer is low and the rain- 
band strong, rain is certain to follow, as it did on the 3rd and 21st 
for example, and when there is a high thermometer and a faint band 
there will be no rain, for instance, the 7fch, 15th, and 20th. 
One great secret of successful rainband predicting seems to lie in 
making proper allowance for the temperature, and the direction and 
force of the wind have also a share in modifying the data. 
2. The Theory of Monopressures applied to Ehythm, Accent, 
and Quantity, By the Eev. J. L. Blake. Communicated 
by Professor Crum Brown. 
3. On the Effect of Oil on a Stormy Sea. 
By Mr John Aitken. 
The calming effect of oil on troubled wafers is so well known 
and so often referred to, that we might have expected there would, 
by this time, have been a considerable amount of written informa- 
tion on the subject. This calming effect of oil is not only well 
