Details
Autograph letter signed ("M. I. Brunel") to I. K. Brunel ("my dear Isambard") at Duke Street, Westminster, 2½ pages, 8vo, with 4 diagrams and integral address leaf, 24th June 1839.
On his method of doweling timber by the use of asphalt and an iron casting, a method he has tested by dropping two sets down the Rotherhithe shaft -- one of these was damaged and he is sending it to his son for examination. With four diagrams, two on the first page showing the dimensions of the timber and the casting, and one on the next of an experimental "coupling," an example of which he is also sending to Isambard.
"The application I have made of Asphalte instead of Mastic for Dowldling Timber has been remarkably satisfactory and does, of course, set in an hour or less. I have thrown two sets, coupled with asphalte from the Top of the Shaft on the Brick work at the bottom. Each set has stood perfectly well, though not in contact, all over merely little more than the casting -- [diagram] thickness of metal 2/10 and only 2in consequently one Inch on each side of the Timber. [diagram] One was damaged and split as you will see, for I select it for you. This, like the others, has has been thrown down from the Top of the Shaft, that is, from the landing of the men, consequently 50 feet yet after having been exposed to the sun the crack was much wider.
"I have a coupling like this which I shall experiment upon as soon as I have leisure. [diagram] I send you one of the pieces in question with the pattern. particularly good," Brunel adds in the post-script, "for coupling Iron with wood or even Stone before putting it on the Track. I have had it struck with a large smith or forge hammer. it was not in the least disturbed ---- witnessed the prints of the blows [diagram]"
On his method of doweling timber by the use of asphalt and an iron casting, a method he has tested by dropping two sets down the Rotherhithe shaft -- one of these was damaged and he is sending it to his son for examination. With four diagrams, two on the first page showing the dimensions of the timber and the casting, and one on the next of an experimental "coupling," an example of which he is also sending to Isambard.
"The application I have made of Asphalte instead of Mastic for Dowldling Timber has been remarkably satisfactory and does, of course, set in an hour or less. I have thrown two sets, coupled with asphalte from the Top of the Shaft on the Brick work at the bottom. Each set has stood perfectly well, though not in contact, all over merely little more than the casting -- [diagram] thickness of metal 2/10 and only 2in consequently one Inch on each side of the Timber. [diagram] One was damaged and split as you will see, for I select it for you. This, like the others, has has been thrown down from the Top of the Shaft, that is, from the landing of the men, consequently 50 feet yet after having been exposed to the sun the crack was much wider.
"I have a coupling like this which I shall experiment upon as soon as I have leisure. [diagram] I send you one of the pieces in question with the pattern. particularly good," Brunel adds in the post-script, "for coupling Iron with wood or even Stone before putting it on the Track. I have had it struck with a large smith or forge hammer. it was not in the least disturbed ---- witnessed the prints of the blows [diagram]"