From Robert Chambers to William Kemp   22 December 1847

Dear Sir,

I have now obtained a highly authoritative statement of the relation of the datum of the Hawick Railway to the sea. The interval between that datum and the point 18 feet on Leith Dock gates (height of ordinary spring tides) is precisely 7 feet 8$\frac{1}{2}$ inches. If we add this to the height of the rails at Dingleton Street, Melrose, we make these just about 328 feet above the sea. This I suppose is now a fixed matter, with which we must be content. It shows my measurements at Portobello, which made out nearly 14 feet of interval, to have been wrong.

On this measurement, Eildon top is 1381 feet 8$\frac{1}{2}$ inches high, if Mr Mitchell is right in giving it as 1053′ 6″ above the rails. The foot of Greenfield at the Calf hill becomes 709 by your list or 700 by Mr Mitchell’s. The shelf which you gave first as about 860 and latterly as a little less, on the presumption of the rails being 334, may now, I suppose, be set down at 872 or 874. It would thus harmonise with my present view of the lowest Glenroy, for I have within a few days obtained a new view of the tides at Inverness which calls for a small difference being made in my estimates of the Lochaber terraces.

I would now beg to call your attention to one or two discrepancies between your measurements and Mr Mitchell’s, which I should like much to have explained. You have the top of Gattonside hills and Housebyres flat at 829; by my very humble attempt, they are 827. But Mr Mitchell gives 797. How could this difference of fully thirty feet arise? Then you have the lower shelf of Black Hill &c. at 912, the upper at 963, being very near my own measurements; but his are respective1y 894 and 932. These differences are the more strange, as his next three levels nearly coincide with yours.

The coincidence of the Eildon terra⁠⟨⁠ces⁠⟩⁠ with those in Glenroy &c. above the 874 is not very happy. They are as follo⁠⟨⁠ws⁠⟩⁠

Glenroy Tweed vale

1196

1165 1172

1085 1083

873-4 872-4

Yet, perhaps, if the Tweeddale terraces could be stated with equal precision to the Lochaber, which are so singularly well defined, they would be found quite the same. Pray see if any latitude is allowed you in your notes as to the heights of the two upper ones, so as to bring them more near to the Lochaber—particularly as to the higher of the two.

Believe me, | dear Sir, | very truly yours always, | R. Chambers.