Recently in the library of Clare College, Cambridge, I have come across a collection of letters formerly belonging to the Reverend W. Williamson who was a fellow and tutor of the College during the first half of the nineteenth century. The majority of these letters are in the hand of James D. Forbes, and as they are of some interest in the history of glaciology I thought it worth while to publish some extracts.

Perhaps the most interesting is the first, of which I reproduce a facsimile. It is dated Tuesday, 27 Augt.,1844, and reads as follows:

My Dear Sir

I have left with Auguste your books & Rulers with very many thanks. We are just starting most reluctantly for Geneva. I trust you will have the fine weather which we are just leaving. On the whole I have no reason to be dissatisfied with my experiments. I have observed a space of 180 ft acroß the flat part of the Glacier of which 90 feet were divided into 45 distances of 2 feet each marked by holes bored in the Ice by a common 5/16 inch drill which I find answer better than anything else, covered with stones. These advanced progreßively & without starts or very slight ones so as to present when I left it a most beautiful curve slightly convex upwards, of which I will endeavour to send you a tracing from Geneva. It seems to me completely to resolve the question of the fluibility of the Ice—but I hope that you will continue your experiments, which I have no doubt that you will do, with similar results.

I mounted up to the height above Trelaporte & saw you reach the Col du Géant.

Believe me Yours Sincerely

James D. Forbes

The Revd.

W. Williamson.

This letter appears not to have been posted, but to have been left at Montenvers for Williamson. It would seem to imply that Forbes made his first observations on a line of holes across the Mer de Glace with some of Williamson’s instruments, and that Williamson was himself engaged in a similar experiment. It was from Williamson that Forbes first learnt of Hopkins’s theoryReference Forbes ¹ in Geneva earlier in 1844, and hence became convinced of the desirability of detailed measurement at closely spaced points along a line across a glacier.

Williamson apparently did confirm Forbes’s measurements, as the next letter is as follows:

Edinburgh 11 November 1844

My Dear Sir,

I fear that I shall appear very negligent of your interesting communication dated so far back as the 19th, Octr. But I shall have your pardon I hope, when I mention that on the night of the 20th. Mrs. Forbes was confined & presented me with a daughter—a very thriving child—but her own health has been so indifferent since as to keep me in a state of haraßing anxiety, from which I am only relieved within a day or two by a fair prospect of recovery. My claß, too, began last week & added to my cares.

Nevertheleß I have been fully alive to the interesting facts which your letter presents, & to the important confirmation which it contains of the views I have published on the real structure of glaciers, which I really believe no one but yourself has yet had the patience to make on anything like the same scale. I hope I may consider myself permitted to make some extracts from your letter if I shall ever be able to publish at length my later observations & speculations on glaciers. I feel somewhat shaken in constitution within a year or two & I feel that Literary Abstinence is my only chance of cure; I am unwilling to write anything which could produce controversy & yet I feel a difficulty in writing without the chance of incurring it.

In broaching a new Theory I felt the extreme importance of including in it no merely hazarded opinions, although they might very likely turn out right, because I know that the retractation of such when honesty requires it weakens immensely the authority of a Theory. I never pretended that I could explain every thing at once; but I was the more tenacious that what I profeßed to explain should not be lightly discarded as unproved.

Now you have got a point of contrary flexure & so have I. I do not pretend to explain it completely, but I request you will consider whether there is not something more than a vague analogy with a river which presents many such flexures; real relative backslidings of particles producing eddies. The same causes which produce unequal velocities in a River will produce them in a Glacier, such as a resisting Promontory, or a Tributary Glacier which, as I have somewhere stated, always (I think) produces an exaggeration of the veined structure. Now you will observe that such an occasional acceleration or retardation is more perpetuated in a Glacier than in a river, because surfaces of discontinuity once well formed, are naturally when re-frozen and filled with blue ice likely to give way in parallel directions. This view is confirmed by the well known irregular & twisted structure of the veins in the Great Aletsch Glacier; a vast ice stream on a small inclination which like the Rhine, or Rhone in its more sluggish parts, betrays a vast variety of independent currents & eddies because the action of gravity is not strong enough to pull all together, & to sink trifling anomalies.

Such at least are my latest thoughts on this curious subject. I had a letter a few days since from Studer who says that at the Milan meeting Charpentier announced himself (to his friends) as a convert to my views.

If you see Heath pray remember me to him kindly—& to Mr. Power if he be still (as I think) of your College.

Believe me, Yours very truly

James D. Forbes.

The Revd. Wm. Williamson Clare Hall Cambridge

Forbes did not succeed in avoiding controversy, for the next letter reads:

My Dear Sir,

In a letter which I had from Ellis some time ago he mentioned the discußion which had taken place at the Philosophical Society on glaciers; & that you & the Master of Trinity had shewn good fight in my defence; a service of which I feel very much the kindneß, for I am chary of my reputation at Cambridge & Mr. Hopkins, from his local influence is likely to have the ear of the rising generation of clever men, who may not yet have learned the difference between a clever mathematician & a physical philosopher.

My reason for writing just now is to ask you to look at two plaster models which I have sent Ellis, & which shew both the linear markings and crevaßes very well.

Believe me, Yours very truly

James D. Forbes.

Edinburgh 22 Dec. 1844 Revd. W. Williamson

I imagine that no reader of this Journal needs reminding who Forbes was, but perhaps a few notes should be appended on the recipient of these letters.

William Williamson was born at Campton, Bedfordshire, in 1804 and educated at Westminster. He entered Clare Hall in 1820, and was second wrangler and won the second Smith’s prize in 1825. After leaving Cambridge he went to Lincoln’s Inn and was called to the bar in 1830, after which he practised as an equity draftsman and conveyancer until he returned to Clare to become tutor in 1839. He was ordained priest in 1842 and took a B.D. the following year. In 1850 he retired from his fellowship and married, spending the rest of his days as rector of Datchworth, Herts. He died in 1875. These biographical notes are based on the information in Venn, J. A. Alumni Cantabrigiensis.

I am indebted to Dr. A. B. Pippard, the Librarian of Clare College, for permission to publish these extracts.