382 Scieiitijic IntelU(/encc — Meteorology. 



observations made by his direction on the Mer de Glace of Cham- 

 ouni, and in which he places entire confidence, it appears that the 

 ice moved no less than 76 feet between the 12th December 1842 

 and 17th February 1843, or at the rate of 13^ inches, per diem, 

 whilst its mean motion during the summer was 17^- inches. 



The author then explained the manner in which he conceives the 

 conoidal structure of glaciers to be due to the varying velocity of 

 different points of their section producing discontinuity by minute 

 fissures, which are infiltrated and ultimately frozen. He had before 

 satisfied himself that the forms of these surfaces are such as the mo- 

 tion of the particles of a viscid fluid, obstructed by the sides and bot- 

 tom of the canal in which it moves, would engender. But to make 

 this more palpable, he has endeavoured to imitate the motion of a 

 glacier, by causing a plastic fluid of different colours to mould itself 

 by the action of gravity in an inclined bed, and he has thus succeed- 

 ed in reproducing the forms of the structural surfaces of glaciers so 

 precisely that they cannot be distinguished from the curves which he 

 had drawn as representing the actual phenomena. — See Edinburgh 

 Philosophical Journal, Oct. 1842, pages 346, 347.* 



Professor Forbes recapitulated the proofs that the glacier moves 

 as a plastic mass, the friction of whose parts is less than their fric- 

 tion upon the sui'face over which they tend to slide ; and he bases his 

 theory upon three classes of facts, which he considers that he has 

 demonstrated, 1. That the glacier moves like a stream, fastest at 

 the centre. 2. That its velocity is immediately governed by the 

 external temperature and the state of infiltration of the ice by water 

 at the time. 3. That the forms which its veined structure a«iunies 

 are those due to the movement of a semi-solid mass in the manner 

 supposed. 



3. Climate of Malta. — Many of the remarks which have been 

 made on the Ionian Islands, in relation to climate and seasons, are 

 necessarily applicable to Malta. Situated farther south, its mean 

 annual temperature is higher ; its surface being less elevated, its 

 highest hills not exceeding 600 feet ; and being farther removed 

 from lofty mountains, and surrounded by a greater expanse of sea, 

 its temperature during the greater part of the year is more equable ; 

 and lastly, being nearer to the coast of Africa, it is more liable to 

 be invaded by hot winds, and in summer to experience excessive de- 

 erees of heat. 



* Our readers are requested to correct a typographical error at line 6. p. 3.52, 

 Tol. xxxiii, viz., for annular rings, read annual rings. — Edit. 



