xviii                                PREFACE

and help of all kinds. To the President and Council of
the Royal Society I offer my sincere thanks for permission
to examine the Oldenburg Ms. correspondence in their
archives. To Colonel Hanna I am grateful for his liberality
in communicating to me the valuable original paintings
which have added so much to the enrichment of this
volume; and to Dr. V. Ball, F.R.S. of Dublin, for his aid
with regard to Appendix II. My thanks are also due to Mr.
George Scharf, C.B., and his assistant Mr. L. G. Holland,
for their kind aid in the matter of the description of the
Oldenburg portrait. To my kinsman, Archibald [David]
Constable, I can never sufficiently express my obligation
and sense of the valuable suggestions his oft-tried literary
judgment so freely placed at my disposal at all times.

Following the traditions of my forefathers, I have done
my utmost to enlist the skill and knowledge of craftsmen
of our own country, as an aid to my project; and I believe
that whatever may be the literary defects of this edition,
only too well known to myself, its mechanical production
does credit to my friends and fellow-workers, Mr. Allan
Wyon, F.S.A., Chief Engraver of Her Majesty's seals;
Messrs. T. and A. Constable, Her Majesty's Printers for
Scotland; Messrs. M'Lagan and Cumming, Lithographic
Artists, of Edinburgh ; Messrs. Walker and Boutall, Auto¬
matic and Photographic Engravers, of London; Messrs. J.
Bartholomew and Company, Geographers, of Edinburgh;
and, finally, to my binders, Messrs. Matthew Bell, Colley,
and Company, of London, who have received all my sug¬
gestions, and given effect to them, in a spirit which has
largely aided me in elaborating my designs for the
standard binding of this Series. Messrs. Bell and Colley
have also, I am comforted to think, long since forgiven
me for suggesting the punning device on the binder's
ticket, which has been prepared for use throughout my
Publications.

A. C.

Brondesbdry,
wth November 1891.