128 NORTH UIST. PEAT. 



being formed into a compact charcoal fit for the pur- 

 poses of the blacksmith. The introduction of a few 

 remarks on the formation of this substance will hardly 

 be deemed to require excuse, as it is a question in- 

 timately connected with geology. 



THE subject has indeed been so frequently examined 

 that but little remains to be said on it: had less been 

 written it would not perhaps have so often been in- 

 volved in unnecessary obscurity. 



Agriculturists have distinguished it into several varieties, 

 partly determined by its situation, and partly by cor- 

 responding changes of texture. It is not necessary to 

 follow them further than merely to remark, that ac- 

 cording to the nature of the substratum, the drainage 

 or lodgement of water to which it has been exposed 

 during its formation, and the plants which enter into 

 its composition, it presents differences of aspect, with 

 some slight variations in its chemical qualities ; the 

 latter corresponding to the extent of change the con- 

 stituent vegetables have undergone. 



In general it forms but a single stratum bedded on 

 the rock, or on the alluvial matter above. Occasion- 

 ally however it is found alternating with sand, clay, 

 gravel, or shell marie. The latter alternation is the most 

 remarkable, and occurs only when the peat has been 

 formed under water, or when, after the drainage or extir- 

 mination of a lake, it has grown above the decomposed 

 mass of fresh water shells which occurs in those places. 

 The former alternations occur either from the blowing 

 of sand on the sea shores, or from deposits of alluvial 

 matter brought down by mountain torrents. 



Although fragments of trees are frequently found 

 buried in it, these are not essential. They must be 

 considered as accidental substances, and occur in those 

 cases where it has been formed in forests, partly from 



