380 Obituary—John Francis Walker, M.A., ete. 
value of such work to us. It is just such work that we need, to 
put our ideas into more distinct and scientific forms; and modern 
chemistry will evidently do this service more rapidly than we could 
have hoped. Mr. Perman’s salts were no doubt more tractable than 
those that are the components of rocks, but then it is quite certain 
that his agencies have been applied to rocks fully in proportion to the 
refractoriness of their materials. And Adams’s experiments upon the 
flow of marble show that some rocks, at any rate, are not beyond 
the power of laboratory treatment. 
In this Magazine for May, 1903, I attempted to apply the work of 
Roberts-Austen on the Diffusion of Metals to the Diffusion of Granite 
anto Crystalline Schists, and, at the close of my paper, I dwelt on 
difficulties arising from the heterogeneity of the materials of rocks. 
But it is clear that chemical reaction between solids adds vastly to the 
possibilities of solid diffusion unaided by such changes, and a hope of 
further information of the kind is expressed in the concluding 
paragraph of the paper quoted. 
Geologists will look forward with interest to the full text of 
Mr. Perman’s paper, and hope that he will pursue these researches 
further still. EpwarD GREENLY. 
OS SPAS aa 
JOHN FRANCIS WALKER, M.A.,F.L.S.,F.I.C.; F.G:S.,F.G_S: 
FORMERLY FELLow or Srpney Sussex CoLnece, CAMBRIDGE. 
(WITH A PORTRAIT, PLATE XYLI.) 
Born Noy. 25, 1839. Dizp May 23, 1907. 
Aux lovers of Yorkshire may well feel proud of the many eminent 
geologists who either claim it as their birthplace, or have adopted this 
grand county, so rich in geological and paleontological interests, as their 
home. One recalls to mind the names of some belonging to the past 
and some still present with us: Young and Bird, Dr. Wm. Smith, 
the Williamsons, Martin Simpson, W. Vernon Harcourt, John Phillips, 
Dr. H. C. Sorby, Dr. Murray, J. Leckenby, Sir Charles Strickland, 
Dr. John Lycett, Rey. Professor J. F. Blake, W. H. Hudleston, 
Dr. Reed of York, Professor L. C. Miall, Ralph Tate, Jas. Wm. Dayis 
of Halifax, Dr. Tempest Anderson, Samuel Chadwick, G. W. Lamplugh, 
and many others. ‘To those worthies whose names are inscribed upon 
her past records, must also now be added that of John Francis Walker. 
- Born at York, Nov. 25th, 1839, J. F. Walker was, by inheritance, 
a Freeman of that city, where his family had resided for several 
generations, his grandfather having held the office of Sheriff in 1841. 
At an early age he commenced his education at St. Peter’s School, 
York, and at 18 he became a student at the Royal Agricultural 
College, Cirencester, where under Dr. Voelcker, F.R.S., Professor of 
Chemistry, and Professor James Buckman, F.G.8., Professor of Natural 
History, he imbibed that earnest love of chemistry and geology which 
had such an important influence on his future career in life. In 1862 
he entered Sidney Sussex College, Cambridge, and was bracketed first 
in the Natural Science Tripos in 1866. From Cambridge, after taking 
