lift bodily, displacing the whole of the stonework above.

Surface decay. It is necessary to emphasise the fact that, although surface decay is one of the defects to which the stone is subject, yet it is the least important of all, and is not the cause of the dangerous condition which exists in many parts of the building. The stone has failed, principally on account of geological faults, including the innumerable irregular cracks and joint planes. A stone containing those planes invariably fractures, with the result that there is a possible collapse of those portions which are not held in position by superimposed loads. Even in those cases the sliding joint planes are the incipient cause of structural failure.

3. EFFORTS TO ARREST DECAY: CONSIDERATION OF VARIOUS STONE PRESERVATIVES.

Methods considered by Committee of 1861.-The Committee of 1861 referred the question of stone preservation to the professional chemists among their number, who reported that it was neither necessary nor desirable to proceed with the general coating, painting, oiling or washing of the whole structure, and that it would be sufficient to deal with the surfaces of stones already showing symptoms of decay. They recommended that where decay was due to the action of the weather on exposed surfaces of cornices, string courses, etc., zinc or lead coverings should be fixed, and that in extreme cases the decayed stone should be cut out and replaced by new stone. The full Committee finally expressed the opinion that decay had in no case been arrested by any method of treating the stone, and were unable to recommend any of the processes submitted to them, though they believed a solution could be found. They considered the following methods of treatment deserved further investigation.

For permanent protection :—

(1) An application of silicates in various stages of concentration.
(2) Applications of silicates in conjunction with various saline
compounds intended to produce double decomposition.
(3) Applications of hydrofluoric or hydrofluo-silicic acid or of
saline compounds.

(4) Applications of phosphoric acid and acid phosphates.

(5) Applications of solutions of the alkaline earths or their bi-carbonates in water.

For temporary protection :

Beeswax, paraffin, fossil gums, resins, etc., applied in the form of solutions in volatile solvents.

were brought to the notice of the Committee, some of which were clearly attempts to solve the problem with little or no knowledge of the nature of the stone or the problems involved in its preservation. Others were put forward by chemists, based upon some scientific theory. A number of the more likely of these were discussed at some length by the Committee, and a further selection was made and submitted to the Sub-Committee of Chemists for experimental examination and test. Trials were made with them, lasting over a number of years, but eventually not one of them was found of any real utility.

The Committee also recommended that a further series of experiments should be undertaken under expert chemical supervision, but although it appears that these experiments were carried out, no record of the results can be traced.

Early trials by Sir Charles Barry.-For some years previous to the Committee of 1861 Sir Charles Barry had carried out a series of trials with various compositions on portions of the new building showing signs of decay. His attention became fixed on three proprietary processes, and by comparative tests these three were finally reduced to one, a "so called" secret process which, after an experience of eighteen months, Sir Charles Barry pronounced to be satisfactory. At the time of his death in 1860 the adoption of this process for treatment on the new builing was under consideration. Mr. E. M. Barry, who succeeded his father as architect for the building, was not, however, so confident as to the success of this process. After further trial without any satisfactory results the process was dropped, pending the appointment of the Committee of 1861. Careful inspections have been made in recent years of the portions of the stonework known to have been treated, but no difference is noticeable in comparison with the surrounding untreated stonework. The period of eighteen months upon which Sir Charles Barry would appear to have based his hopeful estimate of the results of the secret process referred to, is now known to be much too short for the formation of a reasonable judgment as to the effectiveness and permanence of any process of stone preservation. His Majesty's Office of Works, since the establishment of its Historic Buildings and Ancient Monuments Section, has tested a great number of so-called preservative processes. Certain of these were proposed by chemists, and included, among others, such processes as Professor Church's Baryta Water treatment, the five classes of solutions of chemical salts for permanent treatments, and the solutions of organic substances for temporary treatments, which the 1861 Committee considered deserving of further investigation. The latter class at least has been considerably extended since the sitting of the Committee. Those processes examined by the Office of Works include also a considerable, still increasing list of proprie

quite empirical, and some unconscious repetitions, under new names, of formulas already tested and proved to be unsatisfactory.

Information from other countries. In 1913 information was sought through H.M. Ministers at Washington, Athens, Berlin and Rome, as to how the problem of stone preservation was being dealt with in those countries, but the replies add little to the knowledge which we already possess and only show that other countries are faced with the same problem, without having found a remedy.

Appointment of committee on stone preservation.-To sum up, no practicable method of preventing the decay of stone has yet been discovered. An expert committee has, however, now been appointed by the Department of Scientific and Industrial Research to consider the whole question.

4. PROGRESSIVE NATURE OF DECAY-PRECAUTIONARY MEASURES TAKEN TO OBVIATE DANGER RISKS.

During the period from 1861 to 1913, nothing material was done either to investigate the causes of the decay or to find means of preventing it. Systematic, but partial, repairs were carried out as they became necessary, but it has since been found that the decay was proceeding immediately around the repaired stone. Since 1913 the building has been under closer observation, and in 1920, when large fragments of stone fell from the main entrance to the Victorian Tower, it was decided to undertake a systematic examination of the whole external surfaces of the building and to remove, by hand, any fragments of stone which were in danger of falling.

Extent of decay.--The whole of the wall surface has been examined at least once with the exception of the plain ashlar in the inner courts, which does not appear to involve serious danger, and this survey has shown the enormous extent and serious nature of the decay and cleavage in every portion of the building. An example of the progressive character of the decay is shown on the Victoria Tower where certain of the decorative heraldic figures were carefully examined and passed as apparently sound in 1923, and yet on re-examination in 1924 were found to have developed fractures involving their entire removal.

Removal of loose fragments.-Prior to 1920 at least 70 tons of loose fragments were repaired or re-fixed, and since that date a further 103 tons have been removed by hand as dangerous to members and the public. Another 25 tons are ready for removal, making a total of 198 tons, or nearly 3,000 cubic feet of stone which

(34,3566)

A 4

fractures and cleavages and will eventually have to be removed.

Effect of hand-picking on appearance of building.-The effect of hand-picking, in denuding the building of its decorative features, is already noticeable in the case of the Central Tower, the pinnacles on the terrace, etc., and the time has arrived when a decision should be reached as to the character and extent of the repairs which must be undertaken. The hand-picking of loose and dangerous fragments must proceed concurrently with any scheme of repair, but when carried out alone it is uneconomical, as the cost of scaffolding is heavy and no permanent results are achieved.

Cost of hand-picking.-The total cost of "hand-picking " to date, including the provision of scaffolds, cradles, etc., is £34,000, to which must be added £6,300 for general maintenance and minor repairs to the stonework since 1914, making a total of £40,300, of which approximately £9,000 was for scaffolding.

5. PROPOSALS FOR THE RESTORATION OF THE
STONEWORK.

(a) AREA TO BE DEALT WITH AND CONDITIONS GOVERNING REPAIR.

In considering a scheme for repair it is necessary to bear in mind the immense area covered by the building, and also the height of the different sections which varies from 80 feet-the average height-to 330 feet-the height of the Victoria Tower. The total superficial area of the masonry including external surfaces of all façades, towers, courtyards, etc., is 900,000 square feet, and the approximate cubic contents of stone is 775,000 cubic feet, exclusive of Westminster Hall.

Conditions governing repair. The following conditions should apply to any scheme of repair :

(1) The stone used for the repairs should harmonise as far as possible in texture and colour with the existing stone, but should be free from its defects.

(2) The general architectural design of the building should not be changed, and the Gothic detail should be preserved, subject only to such modifications in execution as are proved to be necessary.

(3) The faulty methods of construction in the original building, such as the use of iron tie-rods, standards and wedges, should be avoided.

It is essential that non-corrosive metal should be used at all points where it is in direct contact with the masonry. Where vanes are held by heraldic lions, such as at the foot of the lower slope of

the lower slope of the Central Tower, the standards if renewed, should be in bronze throughout, as they pass through the bodies of the heraldic beasts.

(b) EXTENT TO WHICH DETAILS SHOULD BE Reproduced.

Omission of unnecessary detail.-As the Houses of Parliament is a period building, it is essential in any scheme of repair to preserve the details so far as is necessary to retain the architectural character of the bullding; but some modification may well prove necessary in view of the difficulty of carving in a hard stone, and also of the necessity for keeping the cost within reasonable limits.

It should be possible, for instance, where repair of detail has to be undertaken, to omit what may perhaps be regarded as unessential features, such as the extreme elaboration of carving in parts of the building not visible from the ground. In some instances this appears to have been done by Sir Charles Barry himself, unless the carving was omitted by inadvertence during the progress of the contracts. Further, in order to make the repair of irretrievably ruined architectural features and details more permanent than they could ever be in their original form, it may well be advisable to consider modifications in the execution of free-standing and over-elaborately carved ornament. (See photographs Nos. 16 and 17.)

Much of the detail, such as the crowns standing on the small free shafts or pillars rising above the parapets on many of the façades of the building, is so attenuated by cutting away as to be quite unfit and dangerous when executed in stone, particularly in the acid-polluted atmosphere of a modern city. Out of hundreds of these crowns in the original stone all except five have perished, and have been reproduced in cast iron. Another example of unjustifiable freedom in carving is the open-work royal semi-crowns of various sizes in all parts of the building. (See photographs Nos. 18 and 19.) Some of these semi-crowns high up on the Victoria Tower are 3 feet in diameter and project 18 inches in free cut-work. Many have been removed in the process of "hand-picking," and those which remain are a constant source of danger. In the work of repair the external form of the semi-crowns can be preserved but, instead of cutting away freely the whole of the interior, they can be carved with an infilling to represent velvet, giving them a solid bedding into the facework, and losing little, if any, of the architectural effect, while meeting the requisite conditions of strength, permanence and economy. (See Drawing No. 21.)

Another typical form of excessive workmanship in stone, is the multiplicity of delicately carved stone ornament, so minute in scale that its effect cannot be appreciated except from scaffolds. (See photographs Nos. 11, 19 and 20.)