160 Mr Wilson on the Introduction of' 



ice veins, which penetrated obliquely downwards, partly to the 

 bottom of the vessel ; they had a breadth of from half to three 

 quarters of an inch, and were quite empty of the frozen mud. 



The frozen mud, separated as much as possible from the 

 transpareni ice, gave, when thawed, a moist mud, so that crys- 

 tallization had produced no more complete separation than sim- 

 ple rest ; but the ordinary separation of the water from the mud 

 was produced in a much shorter time than by the mere opera- 

 tion of specific gravity in the mechanical mixture. 



With regard to the causes of the three different appearances 

 that I have enumerated, they appear to me to depend upon 

 differences in the excess of water in the mud, on the tempera- 

 ture of the mass before it is exposed to congelation (sometimes 

 boiling water was used), and especially the rapidity of the con- 

 gelation. Farther I can give no explanation. 



Account of the Introduction of the Wood^Grouse or Capercailzie 

 (Tetrao Urogallus) to the Forest of Braemar. By James 

 Wilson, Esq. F.R.S.E., M.W.S., &c. Communicated by 

 the Author. 



X HE almost recent extinction in Britain of the largest European 

 bird of the gallinaceous order, is a remarkable fact in the geo- 

 graphical history of, the species. Its rein trod uction is also a 

 circumstance of sufficient interest to deserve a' detailed record. 



The wood-grouse or capercailzie, was formerly a well-known 

 and frequent inhabitant of the Scottish forests. It still occurs 

 in considerable abundance among the wooded and alpine dis- 

 tricts of Europe, especially in Scandinavia. It is rare in France, 

 well-known in Germany, not unfrequent in Switzerland. It 

 spreads through Russia into Siberia, and is very numerous in 

 several districts of the north of Asia. It seems always to prefer 

 mountainous forests, apd is rarely met with in plains or flat 

 countries, however richly wooded. Its favourite trees are pines, 

 birch, and juniper. It feeds on the fruit of the last-named 

 plant, and on the buds and tender sprays of the two former. 

 Colonel Montagu found the crops of two females which he ex- 

 amined, to contain a species of berry similar to the cranberry, 

 called in Norway Tyttehoer; and the tops of that plant, toge- 



