A treatise on the origin, progress, prevention, and cure of dry rot in timber

by Thomas Allen Britton

The process should always be carried out during the spring and early summer months, according to the state of the temperature and the observations of those in charge of the carved or other work, as to the action of the worm, which is manifested by the fine dust falling from the worm-holes, crevices, &c.

Mr. Henry Crace was engaged in 1855 to restore some of the wood carvings in the Mercers’ Hall, London, which had been perfectly honeycombed by a small brown beetle about the size of a pin’s head. The carvings being first washed, a number of holes were bored in the back by a gimlet, and also into every projecting piece of fruit and leaves on the face. The whole was then placed in a long trough, 15 inches deep, and covered with a solution, prepared in the following manner:—16 gallons of linseed oil, with 2 lbs. of litharge finely ground, 1 lb. of camphor, and 2 lbs. of red lead, were boiled, for six hours, being well stirred the whole time; 6 lbs. of bees’-wax was then dissolved in a gallon of spirits of turpentine, and the whole mixed while warm thoroughly together.

In this solution the carving remained for twenty-four hours. When taken out the face was kept downwards, that the oil in the holes might soak down to the face of the carving. The dust was allowed to remain to form a substance for the future support of the wood, and as it became saturated with the oil it increased in bulk, and rendered the carving perfectly solid.

No insect has since been found to touch these carvings, as they could not subsist on this composition.

In 1855 the carvings of Grinling Gibbons, at Belton House, were in such a condition as to render it absolutely necessary that something should be done to prevent their complete destruction. To this end they were placed in the hands of Mr. W. G. Rogers, who undertook to experiment upon their restoration. This gentleman reported that the first step he took was to have the various pieces photographed, as a means of recording the position of each detail of the ornamentation, &c. The whole of the works were in a serious state of decay, portions being completely honeycombed by the worm. In order to destroy or prevent any future development of the insect within the wood, Mr. Rogers caused the whole to be saturated with a strong solution of corrosive sublimate (bi-chloride of mercury) in water. The colour of the wood, however, suffered so seriously by the action of the mercury that it was found necessary to adopt some means of restoring the original tint. (It gives a dark colour to the wood, which is caused by the metal contained in the sublimate.) This was effected by ammonia in the first instance, and subsequently by a slight treatment with muriatic acid. After this the interior of the wood was injected with vegetable gum and gelatine, in order to fill up the worm-holes and strengthen the fabric of the carvings. A varnish of resin, dissolved in spirits of wine, was afterwards spread on the surface, and then the dismembered pieces were put together in conformity with the photographs taken, as records, prior to the work of restoration having been commenced.

In order to ascertain the present condition of these carvings, seven years after the operations detailed had been completed Mr. Rogers communicated with the Hon. Edward Cust, one of the trustees of the Earl Brownlow who desired him to communicate with the clerk of the works at Belton. Mr. G. A. Lowe. Mr. Lowe, in writing to Mr. Rogers, informed him that “there is never any appearance of worm dust from the very beautiful carving by Gibbons since you preserved it some years back.”

Mr. Rogers stated, at a meeting of the Royal Institute of British Architects, a few years since, that similar carvings at Ditton Park, Cashiobury, and Trinity College, Oxford, are in a state of decay, the surface or skin, in some instances, being, covered with a deceptive white vegetable bloom, which assists in completing the work of destruction.

Painting hastens the work of destruction. In the library of Trinity College, Cambridge, some of the finest carved work at some former time was thickly painted over, preventing the escape of the insects within, which were compelled to feed on the last bit of woody fibre, leaving nothing but the skeleton of what it once was. At Cashiobury, where can be seen room after room of the finest of Gibbons’ work, all this charming carving (about thirty years ago) was covered over and loaded with a thick brown paint and heavy varnish, destroying all the delicate feathering of the birds and veining of the leafage, the repairs being done in plaster or a composition. Flowers, each about the size of an orange, were thus left with nothing but a skin of dust, with just enough fibre left to save them from collapsing in the handling. All the glorious work of Gibbons in the chapel of Trinity College, Oxford, was some years since covered with a dirty, undrying oil.

We dislike painters who paint carvings as much as the servant who applied to Mrs. H—— (wife of the celebrated landscape painter) for an “appointment” as cook, and having ascertained that the master of the house was a “painter,” remarked, “I cannot take the situation, ma’am, as I have never lived in a tradesman’s family.”

It is a difficult process to remove paint from carvings, as it is not possible to scour and wash it off in the ordinary way: it must be eaten off by an alkaline solution.