500 Proceedings of the Royal Society of Edinburgh. [Sess. 
sought by Sir John Murray in connection with the observations of seiches 
on the Scottish lakes. This Sir John proposed to make part of bis general 
survey of the fresh-water lochs of Scotland, and to this end he set up 
forms of limnometer which had been designed by Forel and others in 
Switzerland. The problem was just the kind to awaken Chrystal’s keenest 
interest. It involved hydrodynamical problems of great difficulty, which 
could be surmounted only by use of mathematics of a high order. It de- 
manded experimentation of an enticing nature, full of difficulties, and ever 
presenting new conditions to be considered. Into this work Chrystal 
accordingly threw himself wholeheartedly. Not only so, but he drew 
round him a devoted band of helpers, who accumulated new data by patient 
observation along the shores of several Scottish lochs, and who also arranged 
under his supervision ingenious experimental models of seiche phenomena 
in lakes. His papers on this subject, which will be found enumerated 
below, are recognised as among the most important bearing upon the sub- 
ject. For this work he was awarded the Gunning Victoria Prize by our 
Society and a Royal Medal by the Royal Society of London. 
His seiche investigations brought him into close touch with F. A. Forel, 
the veteran naturalist of Lake Geneva, whom he advised the Council to 
invite to deliver an address to the Society. This Professor Forel did in 
the summer of 1911. Unfortunately Chrystal was at the time too ill 
to receive the genial Swiss or to listen to his interesting lecture on the 
Fata Morgana. 
To our Society Professor Chrystal’s family have gifted his unique 
collection of books and papers bearing on the subject of seiches; these, with 
copies of his own valuable contributions, are now arranged, partly chrono- 
logically, partly according to size and country, in several volumes, which 
cannot fail to be for the future student a most important compendium of 
literature. 
Chrystal’s last published paper, “ On the Theory of the Leaking Micro- 
barograph,” is, in a sense, a continuation of his investigations into the causes 
of seiches. It has, however, a much wider application, and is an important 
contribution to the theory and method of observation of small and rapid 
barometric fluctuations. 
The list of papers appended is for the most part arranged in chrono- 
logical order. 
