158 The hish Naturalist. [June, 



did not occur in this country. To these we are not able to 

 add more than two others. The occurrences are as follows : — 



A.D. 1763, Autumn. Stuckhauser bogs, Treuenfeld, Duchy of 

 Oldenburg.^ 



A.D. 1772, Deccmlbcr 16. Solway Moss, Cumberland, England.' 



A.D. I87I, November 29. Stanley, Falkland Isles, off Cape Horn.' 



A.D. 1886, ^\xr\2i 2. Stanley, Falkland Isles.-* 



The recorded outflows in Ireland and elsewhere differ partly 

 in magnitude, but chiefly in the rapidity of flow of the escaping 

 material. The rate of flow is evidently a function of the slope 

 of the ground and the viscosity of the fluid, and the latter 

 depends on the ratio between the amount of water and of 

 solid contents present in the moving material. A difference 

 also exists in the proportion of solid crust to liquid contents. 

 The largest proportion of solid material is met with in the 

 flow of 1745. In this case the bog shifted bodily, and the 

 movement might, with more justice than in most instances, 

 be compared to that of a landslip. The late eruption of 

 Knocknageeha was one of the largest on record, and is also 

 characterised by the unusually large proportion of water 

 present in the liberated material. Hence its rapid flow. 



Klinge,s the latest investigator of these phenomena, ex- 

 presses views on the constitution of peat bogs differing in 

 some respects from those usually accepted. He labours to 

 prove that the absorption of sub-aerial water, or the develop- 

 ment of large quantities of gas, are insufficient to account for 

 the bursting of bogs. He regards mountain bogs as of two 

 different kinds, those which have grown in the uniform 

 climate of the western coast of Europe, characterised by a 

 continual increase in the degree of decomposition from their 

 surface downwards, and those which have arisen under the 



^Lesquereux, Untersuchungen iiber Torfmoor: German edition by 

 Ivengerke, with remarks by Sprengel and Lasins, 1847, p. 165, Anmerk. 



' Lyell : Principles of Geology. 



3 Extracts from a letter by Acting Governor Bailey to Governor 

 Callaghan. Quarterly Journal of the Geological Society^ vol. xxxv., Proceed- 

 ings, pp. 96, 97, 1879. 



* Extracted from a letter by Lieut. Governor of the Falkland Islands, 

 Arthur Barkly, to the Rt. Hon. Earl Granville. Quarterly Journal of the 

 Geological Society, vol. xliii., Proceedings, p, 2, 1887. 



'^ Ueber Moorausbriiche, Botanische /ahrbiicher, Bd. xiv., 1892, p. 426. 



