Marvels of the Universe 631 
natural law that the freezing-point of water is 
lowered by pressure. 
Tyndall describes Ice Flowers ofa totally 
different nature to those which adorn the 
frozen surface of alake. These flowers actually 
lie beneath the surface of the ice. A slab of 
ice is placed in the path of a concentrated ray 
of sunshine. Part of this beam is stopped. 
Part goes through. “The former produces 
internal liquefaction ; the latter has no effect 
whatever upon the ice. But the liquefaction 
is not uniformly diffused. From separate 
spots of the ice little shining points are seen 
to sparkle forth. Every one of these points 
is surrounded by a beautiful liquid flower 
with six petals. . . . This is a reversal of the 
process of crystallization.” 
These Ice Flowers within ice are formed 
through the melting of the spot where the ray 
has been stopped by a crystal, the melting ice 
shrinking in bulk and leaving a vacuum. It 
is the surface of this vacuum, shining like silver 
in the sun, that forms the flowers. They can 
be seen any sunny day with the aid of a 
pocket lens. 
There seems little doubt that the popular 
idea that more frost is needed in England to 
form ice of a given thickness than is required 
in the Engadine, six thousand feet above 
seq. has avy tif basis TI OL. oe ae Photo by) ere (Hugh Main, B.Sc., FES. 
sea, NaS a scientinc asls. 1€ alr-pressure WINGED SEEDS. 
at a great elevation is less than at sea-level, Some plants, such as Honesty, supply their seeds with a fas 
so water at SIx thousand feet above sea papery border, which allows them to be carried far away. —] 3) 
< Cc Y c = x c 
freezes at a temperature which would not 
freeze it at sea-level. The ice of high alti- 
tudes always seems more brittle than English 
ice, and a greater thickness is considered 
necessary before it is safe to venture on it. 
Perhaps this more rapid freezing may partly 
account for the greater size of the Ice Flowers 
in the Engadine than in places some thousands 
of feet lower. 
“ Water: Its Origin and Use,” by W. 
Coles-Finch (Alston Rivers, 1908), is a volume 
which those interested in ice and snow, glaciers 
and rainfall, springs and salt lakes, will do well 
to consult. It has about two hundred illustra- 
tions of water in all its forms, and gives suffi- 
cient preliminary information to prepare the 
; [Hugh Main, B.Sc., VES. 
WINGED SEEDS. 
+ 9 5 Notice how flat the seeds are and how they are packed 
enthusiast for making personal observations. 
close to the thin membrane, which acts as a sail. 
Photo by] 
