328 PROFESSOR FORBES ON THE CLIMATE OF EDINBURGH. 
The Observatory was situated in the town of Edinburgh, about 270 feet above the 
sea.* The thermometer was sheltered by a case well perforated with holes to 
admit the air. It was filled with alcohol, and graduated, not, as now, into 
degrees, but into inches and tenths. But the reference to Fahrenheit’s scale 
becomes easy, since we are told (p. 7), that “the freezing point is at 8 inches 
2 tenths; and the heat of a man in health raises the spirits to 22 inches 
2 tenths.” The former point of course corresponds to 32° Fahr.; the latter was 
found by Dr Martine to be 97° Fahr. by actual experiment on the person who 
graduated the Edinburgh thermometer.{ Hence it is easy to form a table for 
reducing the “Edinburgh Scale” to Fahrenheit’s: but it may be sufficient to 
adopt a reduction which is to be found already made at page xiv. of the prelimi- 
nary matter to the third volume of “ Essays of the Philosophical Society in Edin- 
burgh,” published in 1771. The observations there tabulated are evidently iden- 
tical with the observations already described, although these are not there 
directly referred to. It would also appear that blood-heat was reckoned at 96° 
instead of 97°, as I find by comparing the numbers in the “ Medical Essays” with 
those of the Philosophical Society. If we assume (as is reasonable) MartInE to be 
correct, the numbers in the foregoing tables ought to be slightly raised ; but for the 
mean annual temperature the difference would be less than a quarter of a degree. 
6. Lregret that it is not in my power to throw any light on the name of the per- 
son by whom these records were made; but he was in all probability a medical man. 
7. I ought to add that the barometer, hygrometer, wind, weather, and amount 
of rain, are all carefully entered. The observations were almost invariably made 
twice a-day, the first nearly always at 9 a.m., the second at an hour (usually be- 
tween two and six) which varied with the season of the year. . 
8. Confining our attention to the thermometrical observations, they require a 
correction for the varying hour at which the afternoon observations were made at 
different seasons of the year. Taking a sort of average, I have applied the follow- 
ing tabular corrections to the reduced observations as given in the “ Essays of the 
Philosophical Society” above referred to. The second line contains the reductions 
for the observations made in 1764-70, which will be immediately referred to :— 
Years. Jan. | Feb. | Mar, | April.| May. Baas. Gh. Aug. | Sept. | Oct. | Nov. | Dec. 









—1:3]-1:9|]—1:1|/—1:8}—0°8 | -—0°5|—0°2 
WOA=GOs, aeccwacesoorensces —0°3 nee mae —-21|-17 
+11 ed aaa +1°5)+10/4+1°0)/405 
AGA Op oeccncenscusoses +09 ay: $22/41-4 
9. The earlier of these series of observations, it is to be observed, was adapted 
to the Julian, or old style. These tabular corrections are taken from M. Dovr’s 
reductions of the Leith hourly observations.§ 
* Medical Essays, i. p. 6.—Most likely in the neighbourhood of the present Royal Exchange. 
je Lbidi pasar { Marrtine’s Hssays, p. 48. § British Association Reports for 1847. 

