190 PROFESSOR FORBES ON THE TEMPERATURE OF THE EARTH. 



a peculiar character of the soil or rock whose temperature was observed, it oc- 

 curred to me, several years ago, to make several series of observations, under cir- 

 cumstances as exactly similar as possible, with the exception of the nature of the 

 soil or rock. The neighbourhood of Edinburgh, from its variety of geological cha- 

 racter, offered peculiar facilities for this piirpose ; and the British Association, at 

 my request, undertook the expense of providing and inserting thermometers in 

 three different positions, at depths corresponding to those already employed at 

 Brussels, namely, 3, 6, 12, and 24 French feet below the surface. The results have 

 already been partly published in the Proceedings of the British Association, and 

 of the Royal Society of Edinburgh. Deeming it advisable that the curves contain- 

 ing the details of the observations should be published at large, I requested per- 

 mission from the Committee of Recommendations of the British Association, in 

 1 845, to communicate them, for this purpose, to one of the Royal Societies ; and 

 the Council of the Royal Society of Edinburgh having agreed to be at the neces- 

 sary expense of the plates, I am enabled to present the results in their present 

 complete form, and founded upon five years' observations. 



II. Leslie's Observations at Ahhotshall, in Fife. 



I shall here reproduce the particulars of the observations of the temperature 

 of the ground at Abbotshall, in Fifeshire, on the property of Raith, close to the 

 town of Kirkcaldy. The distance from Edinburgh is sufficiently small (11 miles 

 in a right line) to render these observations comparable with ours ; but I quote 

 them more particularly, because those who have hitherto made use of them, being 

 unaware of the original account published by Sir John Leslie,* have made almost 

 every possible mistake as to the locality, circumstances, and depths of these ob- 

 servations. It will be seen that they were made by Mr Ferguson of Raith's 

 gardener. The following extract contains all the important details. 



" In order to throw distinct light on a subject so curious and important, Ro- 

 bert Ferguson, Esq. of Raith, a gentleman whose elegant mind is imbued with 

 the love of science, caused, lately, a series of large mercurial thermometers, with 

 stems of unusual length, to be planted in his spacious garden at Abbotshall, about 

 50 feet above the level of the sea, and nearly a mile from the shore of Kirkcaldy, 

 in latitude 56° 10'. The main part of each stem having a very nan'ow bore, had 

 a piece of wider tube joined above it ; and, to support the internal pressure of the 

 column of mercury, the bulbs were formed of thick cylinders. The instruments, 

 inclosed for pi'otection in wooden cases, were then sunk beside each other to the 

 depths of one, two, four, and eight feet below the surface, in a soft gi-avelly soil, 

 which turns, at four feet, into quicksand, or a bed of sand and water. These 

 thermometers were carefully observed from time to time by Mr Charles Norval, 



* Supplement to the 6th edition of the Encyclopedia Britannica, article Climate, incorporated in 

 the 7th edition. 



