Dear Geoffrey,

I am interested to learn of plans for your exhibition of John Clerk of Eldin's etchings, to take place in Edinburgh at the end of the year. Although I am familiar with some of his etchings, my interest in Eldin is primarily geological, as one who has a particular admiration for his ability to perceive sub-surface geology in the third dimension, as revealed in the unpublished drawings prepared as illustrations to James Hutton's 'Theory of the Earth'. When teaching geology courses in Perthshire some years ago, I used to include a talk about the history of geology, and some of the key figures in this story. I also used to visit Glen Tilt, to pay homage to Hutton at the 'classic' exposure which he visited with Eldin in 1785, where he was able to demonstrate the igneous origin of granite.

It was when crossing the bridge at Dail-an-Eas (‘field of the waterfall’) by Forest Lodge, that Hutton observed the mixture of granite with the local schist. In Hutton's own words "...the granite is here found breaking and displacing the strata in every conceivable manner, including the fragments of the broken strata, and interjected in every possible direction among the strata which appear". Sadly the bridge has since fallen, leaving only the abutments. However, visitors to the website may be interested in two images of the bridge and waterfall which are preserved at Blair Castle. One is a watercolour by John 'Warwick' Smith (1749-1831) executed c.1790, the other a sketch by Lady Emily Percy (1789-1844), daughter-in-law of John Murray, 4th Duke of Atholl – see attached images. Please note that these images are copyright of Atholl Estates, and should not be reposted or reproduced without permission. I was fortunate in obtaining proof copies of two prints made from Eldin’s drawings - one of the exposure in the bed of the River Tilt, the other of two boulders illustrating the junction of the granite and schist. These have been framed and now hang in the hallway at the foot of the stairs in my house.

Christopher Dingwall, Perthshire (HOGG)