not
blacken it at all. Again in Chemistry, if such a substance as gum
guaiacum is converted to a green colour by violet rays of light, its
proper primitive colour can be restored by red rays. It is therefore
fair to infer that the brilliant red of the Ruby is potential for
subtle physical effects, whether beneficial, or the reverse.
On
exposure to a high temperature the Ruby becomes green; but after
cooling it regains its original colour, this behaviour showing the
presence of Chromium. The simplest test of a true Ruby is its hardness,
which is great; the sharp edge of a Corundum crystal will readily
scratch either a Spinel, or a Garnet; but it has no effect on a Ruby.
The
largest Ruby known in Europe is said to be a stone in size that of a
hen's egg (small), which was presented by Gustavus Third to the Empress
of Russia, whilst he visited St. Petersburg. When Peter the Great, Czar
of Russia, came to England, 1697, (working as a shipwright in the
Dockyard at Deptford), he paid a visit to King William the III., whom
he had met before at the Hague; and in taking final leave of whom Peter
fumbled for some minutes in his waistcoat pocket, presently drawing out
therefrom a small parcel wrapped in a shabby scrap of dirty brown
paper. This he pressed into the hand of King William ; it was a Ruby
worth ten thousand pounds. The Czar next went from England to Vienna.
He had previously learnt ship-building in the Dockyards of Holland,
wdiere he was awarded a Certificate of Efficiency in all handicrafts
connected with that business, by the head of the said dockyards.
Peter's curiosity was insatiable ; he was a man of singular magnetic
powers, and endowments : possessing, moreover, a wonderful way of
assimilating all the good
