76 
PASSAGES FROM POPULAR LECTURES. 
another may cause derangement whichever way the change is 
made, from hard to soft or soft to hard. Dr. Parkes thinks 
that the permanent hardness is of more consequence than the 
temporary, and that calcic sulphate, magnesic sulphate, and 
calcic chloride disagree in smaller amounts than carbonate of 
lime, also that less than ten degrees of permanent hardness 
may be injurious to some persons. 
Hard water is supposed to give to horses a staring and 
rough coat, and grooms avoid the use of it as much as 
possible. This would seem to indicate some derangement of 
the system brought about by the hard water. 
It is thought that a hard water keeps better than a soft 
one, and that it is less liable to absorb organic impurities, 
properties of less consequence where there is a constant supply 
than where the supply is intermittent. 
(To be continued.) 
PASSAGES FROM POPULAR LECTURES. 
BY F. T. MOTT, F.R.G.S. 
IV. —F E RNS. 
FROM A LECTURE ON “BRITISH FERNS,” 1875. 
On the face of this remarkable planet there is no more 
remarkable plant than that which we English call the 
Brake-Fern , which the Scotch call Bracken , the Germans 
Saumfarren, the Italians Felce feminina, the Japanese Warabi, 
and the Russians Wodianu.i poporotnik. Common and con¬ 
spicuous in every quarter of the globe, it has perhaps a 
familiar name in a greater number of dialects than any other 
plant. But botanists all the world over know it by the one 
name of Fteris aquilina. 
It is interesting for its beauty, clothing our heaths and 
hills with miniature forests, or standing in motionless armies, 
curled and crested, “ shimmering in the shady wood-light,” 
cool and green while the hot sun blazes in the summer sky. 
It is interesting also as the type of an order of plants remark¬ 
able for their structure, and still more for their history. 
If we say that ferns have been growing in this world for 
ten million years, it is a very rough guess, and must be taken 
only as representing some vast unknown period to which all 
history is as one grain in a bushel of mustard seed. But in 
reading backwards the great inspired Stone-Book, the geo¬ 
logical Bible, on nearly every page which speaks of vegetable 
life there is some record of the ancient family of ferns. 
