650 PROFESSOR PIAZZI SMYTH ON THE 
depends on those characteristics of weather (viz. cyclical returns at several, or many years’ 
interval), which no scientific Society can at present foretell, and no Ministry prevent in their 
destructive effects to the national revenue when they do come” (has been proved in the 
famine history of the past, and may be repeated in the future, for we find as follows in the 
Edinburgh rock thermometers)— 
“1, The most striking and positive feature of the whole series of observations” (viz. of 
the Rock Thermometers at the Royal Observatory, Edinburgh) “is the great heat wave, which 
occurs every eleven years and a fraction, and nearly coincidently with the beginning of the 
increase of each sun-spot cycle of the same eleven year duration. The last observed occurrences 
of such heat wave, which is very short lived and of a totally different shape from the sun-spot 
curve, were in 18348, 1846°4, 1857-8 and 1868°8 ; whence, allowing for the greater uncertainty in 
the earlier observation, we may expect the next occurrence of the phenomenon in or about 1880-0, 
“ 2. The next largest feature is the extreme cold close on either side of the great heat-wave. 
We may perhaps be justified in concluding that the mimimum temperature of the present cold 
wave was reached in 187171; and that the next similar cold wave (7c. similar in being one or 
other of the two satellites attending on the heat wave, though that of 1871-1 was the follower 
of the 1868°8 heat wave, and that now spoken of as to come in 1878°8, is the preceder of the 
expected heat wave of 1880) will occur in 1878°8, 
“ 3. Between the dates of these two cold waves (1871:1 and 1878'8), there are located, accord- 
ing to all the cycles observed,—3 moderate and nearly equi-distant heat waves, with their two 
intervening and very moderate cold troughs, but their characters are quite unimportant as com- 
pared with what is alluded to under heads 1 and 2.” 
(To the above it may now, or in 1880-9, be added—that the following satellitary cold wave 
after the heat of 1880, should occur in 1882, subject to some uncertainties dependent not 
only on the still inexactly ascertained epochs of several past minima, as well as maxima 
of sun-spots,—but on the total inability of all modern science up to its latest advanced position, 
to predict whether the date of the next maximum of sun-spots will be at a long, a short, or an 
average interval after the last minimum. The variations of those intervals in past cycles having 
amounted to anything within three years; an amount of uncertainty far too great to allow of 
useful agricultural warnings.) 
No. V. 
Scottish Meteorological Data of various kinds, arranged either in simple Annual, or more 
generally in Quadruple Annual Means for Cyclical inquiries, 
TaBLeE I, Simple annual Means chiefly for Scawasn’s Sun-spot curves, and Woxr’s dates of 
max, and min. of Sun-spots. 
TasLE II. Quadruple annual Means of the Rock Thermometers, at Royal Observatory, Edin- 
burgh, from 1837 to 1876. Pages 1 and 2. 
Taste III. Quadruple annual Means of Air Temperature, by Scottish Meteorological Society, 
1856-1880. 
TaBLeE LV, Quadruple annual Sums of Scottish Rainfall, by Scottish Meteorological Society, 
1856-1880. 
TABLE YV. Edinburgh Air Temperature by A. Apis, from 1821 to 1850, in Quadruple Ann. 
Means. 
TaBLe VI. Edinburgh Rainfall, by A. Apis, from 1822 to 1850, in Quadruple Ann. Sums. 
TABLE VII. Quadruple Annual Sums of Rainfall, at Culloden, from 1841 to 1862, to fill the 
gap between the last Rainfalls of A. Apiz and the first of the Scottish Meteoro- 
logical Society. 
