174 Proceedings of Societies. 



having a seam of good coal, twelve feet thick, about two miles 

 from the sea; all variously inclined. 



" The coal is interstratified with shales, sandstones, and con- 

 glomerates of quartzose pebbles, with occasional bands of clay. 

 The whole overlying a mass of gray limestone, and apparently un- 

 conformable, but upon this I could not satisfy myself fully ; in- 

 deed it would require a series of observations during many days 

 to describe the district thoroughly, and I have not time now to re- 

 fer to my journal and note book, to refresh my memory fully 

 upon it. The coal measures pass upwards into a friable reddish 

 shale, near Erakle, where they have been baked by volcanic out- 

 pourings, viz., streams cf serpentine, greenstone, and trachyte peb- 

 bles ; and, at Erakle, we have these upper shales on the coast, 

 with some fossil oysters in them of a very small size." 



PROCEEDINGS OF SOCIETIES. 



Royal Society of Edinburgh. 

 Monday, Dec. 4, 1854. Right Rev. Bishop Terrot, V.P., in the Chair. 



Farther Experiments and Remarks on the Measurement of 

 Heights by the Boiling Point of V/ater. By Professor J. D. Forbes, 

 — This paper is in continuation of one printed in vol. xv. of the Royal 

 Society's Transactions, and in a previous number of this Journal. The 

 object of it is to test the correctness of the method of observation, and of 

 calculating the results, then proposed, and to compare both with those of 

 more recent authors, particularly of M. Regnault of Paris, and of Dr 

 Joseph D. Hooker. 



The author finds the results of his subsequent observations in 1846 in 

 the Alps, up to heights considerably above 10,000 feet, to agree well with 

 those previously published, made in 1842. They combine in shewing a 

 sensibly uniform fall of the boiling point at the rate of 1° for 543 feet of 

 ascent (in a standard atmosphere at 32° of temperature), which differs 

 only 6 feet (in defect) from his previous determination. The average de- 

 viation of the individual results from the formula is only ^ of a degree 

 (without regard to sign). 



Barometer. 



Boiling Point. 



Difference from 

 My formula. 



Difference from 

 Rognault's 

 Formula. 



Inches. 



Fahr. 







20 77 



194 ! 28 



+ 0°22 



+ 0°32 



20-79 



194 33 



- 008 



+ o-oi 



22-40 



19794 



- 0-04 



+ 0-12 



22-67 



198-51 



- 008 



+ 0-06 



2315 



199-52 



- 0-07 



+ 06 



23-35 



199-94 



+ 0-01 



+ 0-15 



23-89 



201-04 



- 0-11 



+ 0-03 



2399 



201-24 



- 0-09 



+ 0-08 



2402 



201-31 



+ 0'04 



- 0-20 



24-105 



201-47 



- 0-17 



+ 0-03 



25-14 



203-51 



+ 0-04 



+ 0-19 



28-49 



209-54 



- 07 



- 0-06 



