92 
NATURE NOTES 
One kind is called alabaster, and is useful for ornamental 
work and statuary, but it is too soft for important and durable 
statues. When calcined, the water, of which nearly one-third 
enters into the composition of gypsum, is driven off. It then 
becomes “plaster of Paris” (much gypsum occurring near that 
city), w’hich when mixed with water, reforms stone. Hence its 
great value as a cement and for making casts for modelling, &c. 
Hydraulic limestone is a peculiar kind containing silica and 
lime disseminated through it. As these ingredients enter into 
chemical union with the lime and water they make a firmer 
cement than mortar, an,d “ set ” under water. 
George Henslow. 
LIMESTONE. 
lAVING read with much interest the paper on “ How 
Scenery is IMade ” in the February number of Nature 
Notes, I feel inclined to give some illustrations of 
what is there said concerning the peculiarities of lime- 
stone that have come under my notice. For I take it that one 
of the special features of these pages is, and rightly so, that they 
contain chiefly the record of what the writers have seen or what 
has come within their personal knowledge, thus furnishing 
readers with new facts and fresh interpretations. 
On looking into Chambers’s “ Encyclopaedia ” I see that the 
chief varieties of limestone are chalk, oolite, compact limestone, a 
hard, smooth, fine-grained rock, generally of bluish-grey colour ; 
crystalline limestone, saccharine or statuary marble. But it is only of 
compact limestone that I shall here speak. 
Of this stone were the hills composed that overlooked, from a 
distance of half a mile, the home of my early days. And then 
from my father’s house straight away to the Bristol Channel, 
about five miles off as the crow flies, the ground was almost flat 
— a Somersetshire moor (locally styled “ The IMash ”), the fields 
divided by water dykes, and having a principal stream called 
“The Gruf River” (“ grut ”=great, what its real name was I 
never heard, or do not remember), splendid grazing land, clayey 
loam. 
The hills near us were covered with trees, except the principal 
feature, the Toot, which rose above Cleeve Woods, with its 
picturesque limestone crags exposed to the cold north-east 
winds that came across the moor. Three valleys or coombes 
divided the uplands in our front, called Brockley, Cleeve and 
Goblin Coombes, the first taking its name from an adjoining 
village and the last obviously from some ghost or other terrible 
story due to overhanging rocks or other terrorising appearances. 
These coombes, which had their mouths towards the sea 
