A. B. Hunt — The Crystallisation of Granite. 399 



According to the evidence all these tourmalines crystallised de 

 novo out of a magma or liquor derived from the solution of the older 

 granite by fluids charged with boron and possibly fluorine, though 

 fluorine is not much in evidence on the eastern side of Dartmoor, 

 which may indeed account for the greater simplicity of the rock. 

 This solution of the rock and recrystallisation of its minerals was 

 suggested by De la Beche, but in my ignorance of that fact it was 

 forced upon me independently.^ 



The narrow granitic intrusions in the Culm grits afford excellent 

 opportunities for observing the effect of the invading liquor on 

 the two sides of the fissure, and we may see that the aluminous 

 interstices between the sedimentary quartz-granules are sometimes 

 tourmalinised and the quartzes occasionally dissolved ; but, for some 

 not obvious reason, the fluid inclusions in my slides stop short at 

 the granite. If tourmaline were a hydrous mineral this might be 

 expected. Is it possible that the water is taken up by hydrous iron- 

 oxide ? This tourmalinisation of the alumina of the grits affords the 

 key to a large group of schorlaceous and altered grits, and shows us 

 how tourmaline may either be crystallised out of a liquor containing 

 all the needful constituents or in clays or felspars which supply the 

 alumina in situ. Tourmaline, we see, is not only an extremely variable 

 mineral in colour, form, composition, and mode of aggregation, but 

 is also a mineral formed under very variable conditions of heat and, 

 possibly, pressure. If thoroughly worked out, each variety of 

 tourmaline would probably not only explain itself but also the 

 minerals with which it is associated. 



We have heard much lately from Professor Frankland,^ Mr*. Wells,^ 

 and others, of the effeteness of our old universities, and of Trinity 

 College, Cambridge, in particular. I fear the charge is true. 

 They have not elucidated tourmaline. Yet there have been among 

 their graduates painstaking students, such as Bonney, Hughes, Teall, 

 Tawney, Harker, Hill, Marr, Sollas, Jukes-Browne, and many others. 

 Trinity College is scarcely responsible for myself, because, although 

 I presented myself for examination more than forty years ago, with 

 a more than average schoolboy knowledge of the works of Page, 

 Yarrell, and Westwood, on geology, ornithology, and entomology, 

 and in the way of mechanics had made more than one steam 

 engine, the College earned my lifelong gratitude by 'plucking' me 

 in classics and giving me a much needed lesson in accuracy. I would 

 not exchange that ' pluck ' for a doctor's degree ; and very thankful 

 I am too that pass degrees in science were not then obtainable. 



Pace Messrs. Frankland and Wells, I admit to being one of those 

 wretched beings who much prefer the golf-links to the laboratory ; 

 and, indeed, nearly all my attempts at natural history (which pursuit 

 has little in common with the modern commercial and remunerative 

 idea of science) have been made sandwiched with shooting, yachting, 

 farming, and even golfing. If, indeed, a new era has now arisen, 



1 Geol. Eep. on Devon and Corwall, p. 387. 



2 Eep. Brit. Assoc, 1900, p. 593 et seq. 

 2 " Anticipations," p. 368. 



