and an inspection of several buildings in London, Liverpool and Manchester has shown that where care has been exercised in its selection the stone is wearing remarkably well, and withstands satisfactorily exposure to a polluted acid-laden atmosphere. A notable example is that of St. George's Hall, Liverpool, where no measurable decay of any kind can be seen after 80 years' exposure. In order to test the suitability of Stancliffe stone for use at the Houses of Parliament, one of the pinnacles of the New Palace Yard front has been reproduced in this material and cannot be distinguished from ground level, from the Anston stone immediately adjacent. The chief disadvantage of Stancliffe stone is its extreme hardness, involving high costs for carving elaborate Gothic detail. It is not, however, so hard as Craigleith stone, nor so difficult to work as granite. It is interesting and important to record that Stancliffe stone was favourably mentioned in the Report of the Commissioners, who chose the stone for the Houses of Parliament, and was actually specified by Sir Charles Barry as an alternative to Portland stone or magnesian limestone for the external facings of the building. It was stated at that time that no defects had been noticed in the buildings for which it had been used, but Anston stone was selected as it lent itself more readily to the elaborate carving. The physical tests and chemical analysis made at that time, showed that Stancliffe stone was practically non-absorbent, and less liable to disintegration than any other stone which was examined. Another sandstone of similar character which was suggested for consideration, is less satisfactory than Stancliffe both on account of its wearing qualities and pinkish colour. A sample, worked into one of the pinnacles in New Palace Yard, shows evidence of vents and faults which are likely in the future to develop into cleavages. (b) ARTIFICIAL STONES. Much consideration has been directed to the possibility of using artificial stones. The great majority are modern productions and their use has hitherto been limited. No building of great size and importance has been constructed with artificial stone in London, much less a building with anything like the monumental and profusely enriched character of the Houses of Parliament. Artificial stones have not been used long enough, nor sufficiently extensively, for any assured judgment to be given as to their durability. They are divisible into several groups, and are generally mixtures of sand or crushed or granulated stone, marble, granite, flints, etc., in a matrix or cementing material which may be either natural or manufactured. Often they are found to be very hard and brittle, and some are more difficult to carve than natural stones. ments of the Houses of Parliament, it would be replacing a natural material by a plastic one. Further, there are few exact repetitions in the enriched work in the Houses of Parliament, and it is extremely doubtful whether, with the large number of moulds, casts, etc., which would be required, artificial stone would be more economical in the end than a natural stone. Quite apart from this, the serious point arises as to the aesthetic incongruity of using for repair (on an Anston stone building of the architectural character and quality of the Houses of Parliament), an artificial plastic material, produced and wrought by entirely different processes. In any case, it is certain that tests carried out over long periods would have to be undertaken before any satisfactory assurance could be given that the use of two such dissimilar materials would prove permanent and satisfactory in the end. (c) TERRA COTTA. Good terra cotta has been proved to have a durability probably greater than that of any natural stone that could be used. It has also a wide range of possible colour, within which it would probably not be difficult to match the tints of the existing Anston stone retained in the work. Again, however, the question of the aesthetic incongruity, raised with regard to artificial stone, arises in considering terra cotta, for by the very excess of its resistance to atmospheric influences and impurities, and by its dull, unaltering texture, it would distinguish itself increasingly in time from the normally ageing and weathering stonework of the rest of the building, with which it would be in close juxtaposition. Practical difficulties as to its perfect manufacture exist. The question of the large number of moulds and templates, etc., required, enhanced as they would be by the risk in firing, would again probably make the total cost, if terra cotta were used, as great as, if not greater than that of any sandstone. For this reason the use of terra cotta cannot be recommended. Stancliffe stone suggested.-On the whole, therefore, Stancliffe stone is recommended for the repairs, and in this recommendation both Mr. Howe and Sir Robert Robertson concur. The Department of Scientific and Industrial Research have also been consulted on the question of the durability of the stone, and have expressed their concurrence in the selection. The quarry from which it is taken is in no danger of exhaustion, and steps would be taken to ensure adequate and regular supplies. Arrangements would be made at the quarry for careful selection of blocks, and in order to minimise the risk of flaws and faults, and to economise in carriage, the blocks would be rough-shaped at the quarry, the finished work being carried out in the immediate vicinity of the Houses of Parliament. Choice of Chilmark stone for the Cloister Court.-The question also arises as to what stone should be used for the portion of the repair. Caen is suitable for the detail, but is liable to decay from atmospheric pollution. Stancliffe stone would show too great a contrast in texture and colour in comparison with the existing Caen stone, and this contrast would be emphasised by time. It is also doubtful if it would lend itself to the fine carving required. The choice is, therefore, narrowed down to a limestone of the same fine grain as Caen, but of greater durability. The Bath stones do not weather satisfactorily in the London atmosphere. Portland and other good stones are unsuitable owing to their unsatisfactory colour or texture. Of the best limestones those that approximate most nearly to Caen stone in colour and texture are Ketton and Chilmark stones, the latter being the better of the two in these respects. Ketton stone was used in the restoration of the west side of Westminster Hall and remains in good condition. Chilmark is a siliceous oolite, i.e., an oolite with an abnormal proportion of silica, and Salisbury-one of our best preserved cathedralswas entirely built of it. It has also been used in the transept fronts and the Chapter House at Westminster Abbey, and has weathered reasonably well; satisfactory strength can be obtained by careful selection at the quarry, and as the colour and general texture are very similar to that of Caen stone, it is recommended that Chilmark stone should be used for the repair of the Cloister Court. 7. ARRANGEMENTS FOR CARRYING OUT THE RESTORATION. Continuous supply of stone.-As soon as the stone to be used has been chosen and the scheme of repair approved, steps must be taken immediately to secure a continuous supply of the best stone over the whole period of the work, and an officer must be appointed to act continuously at the quarry to make the selection. All blocks will be sent from the quarry in the rough and reduced approximately to the dimensions required. Stoneyards. At least two stoneyards should be established adjacent to the building, and it is suggested that these should be placed on the Speaker's Green and the Victoria Tower Gardens at a sufficient distance from the south front of the building to prevent disturbance from the noise of machinery. Scaffolding. For purposes of examination of the stone and hand-picking, light scaffolding has been used and economy effected by the use of hanging cradles for the higher portions of the building. In view, however, of the risk involved in using cradles for the removal of large masses of stone, it will be necessary, in carrying out the proposed repairs, to erect independent scaffolds for each section under treatment. Inconvenience to members and officials.-Every effort will be made to reduce inconvenience to members in both Houses of Parliament to a minimum, but it must be borne in mind that undue restrictions imposed during the continuance of the work will mean greatly and cutting away defective stones is unavoidable. Rate of Progress.--The rate at which the work will proceed will depend to a great extent on the labour available and on the possibility of obtaining sufficient quantities of suitable stone. Commencement should be made on the terrace front, and attention should be confined to those parts of the building in which the condition of the stone constitutes the greatest risk. 8. ESTIMATE OF COST. Estimate only approximate. The difficulty of preparing an accurate estimate will be fully appreciated. It is impossible for instance to foresee how much stone will prove to be defective while the work is in progress, or what changes may take place in working conditions, and in the cost of labour and material. The cost will also depend very largely on the character and extent of the scheme of restoration ultimately carried out. The estimated cost of carrying out the restoration is £1,062,350, made up as follows: ... ... ... Scaffolding, tackle, unloading machinery, plant, ... ... ... ... ... ... ... ... ... ... ... £ 23,000 Dealing similarly with windows on other fronts Repairing Caen stone facades to the Cloister Court... ... actual cost of the erection of the Houses of Parliament was over £2,000,000, or 1s. 8d. per foot cube. At present day prices, and using Stancliffe stone, instead of Anston, the cost would probably be well over £12,000,000 or 9s. per foot cube, the approximate cubic contents of the building being 23,500,000 cubic feet. It will be seen, therefore, that the estimated cost of the repairs represents roughly 8 per cent. of the present day cost of erection, or per cent. per annum spread over 15 years, the time estimated as necessary for the completion of the work. 9 SUMMARY. 1. The Houses of Parliament were erected during the years 1840 to 1852 in the Gothic style to the design of Sir Charles Barry, Anston stone being used for the building. 2. In 1861, signs of decay having already been evident for some years, a Committee was appointed to consider the question. The Committee were impressed with the seriousness of the decay, but did not refer to what has since proved to be the primary cause, namely, geological joints and fractures in the stone. They were unable to discover any satisfactory preservative. 3. Recent investigations have confirmed the view that the decay is due to: (a) Geological joints and fractures in the stone; (b) the effect of atmospheric impurities resulting from the combustion of raw coal; (c) the corrosion of iron tie rods, dowels, &c., used in the construction, and (d) Face bedding, i.e., stone not placed on its natural bed. 4. No satisfactory stone preservative has yet been discovered, and the question is now being considered by an Expert Committee under the Department of Scientific and Industrial Research. 5. In 1920 the decay having been progressive during the intervening years, the condition of the stonework became so serious that it was necessary to carry out a systematic examination of the whole building and to remove by hand portions of the stonework which were in danger of falling. This continual hand-picking has denuded the building of many of its ornamental features, and the time has now arrived to consider a comprehensive scheme of repair. 6. It is now proposed to replace all the defective stone, and after careful consideration of all possible materials, including artificial stone and terra cotta, it is recommended that Stancliffe stone, a silicious sandstone, should be used for the repair of the main portion of the building and that the Cloister Court should be repaired with |