"SERMONS IN STONE."

Dominion, Volume 6, Issue 1777, 16 June 1913, Page 2

"SERMONS IN STONE."

— 0 FAULTS IN THE NEW G.P.O. THE BASE STONE SHOWS WEAKNESSES. If there be "sermons in stone," as Shakespearo would have us believe, a rather salutary one is preached in connection with certain stone used ill tho construction of the new General Post Office. Although it has only been in position some eighteen mouths 'or so, this Btone, which comes from tho vicinity of Greymouth, is developing numerous cracks that run from ono block into another across the seams, laterally, vertically, and on the angle. Further, thero are evidences where big chips are likely to leave blocks, if the cracks develop much more. As far as tho stability of the building is concerned, tho flaws in this base stone count as naught, as it is only used as a veneer, and does not carry any weight to speak of. Tho stone is but a ton or twelve-ineh veneer. Tho weight of tho buildiig is taken by the 21ft. brick wall against wliich tho stone in question rests. What, however, should be made quite clear, is that the faults discovered do not refer to the Tonga Bay granite, with which the main building is constructed. Mr. T. S. Lambert, expert in stones, and who in 1890 reported on New Zealand building stones on behalf of the Government, states that the matorial used in the base of tho new Post Office is nothing but a sandstone (compressed sand), and of a quality that is always more or less affected when exposed to the air, particularly the air of a city, where tho sulphuric acid from the smoko affects it considerably. The cracks that were developing in so many places had nothing whatever to do with any strain imposed; ! it was tho result of shrinkage caused by exposure to tho air. Not only was it cracking, but there were many places whero it was "fretting" or piw'denng in patches, and ono could rub it off with the hand. That would continue as time went on, as the stone was not calculated to stand such exposure. "It is really not a stone at all." said Mr. Lambert. "It is compressed sand solidiliecl into a.dSnso form by pressure applied over, probably countless ages of time. Tho discolouration that is seen hero and there is due to the presence of vegetable matter, seaweed, and such like, which has been crushed into tho stone in tho process of consolidation. There is, too, I think a percentage of magnesia in it. Columns and pillars of such stone would probably last a long time in pure air, or in tho interior of a building, where they were not exposed to the elements, but it is not a stone to bo used where it is exposed to tho weather and the smoke of a city—that is, if it is wanted to last. _ "Look hern!" he said, indicating a patch. "I can scrape it away with my hand—it powders easily." And one could seo tho powdered stone dropping off as he scraped the block with his fingers. On being consulted, Mr. A. Wilson, of the firm of J. and A. Wilson, the builders of the new G.P.0., stated that if tho necessity did arise, there would not bo any great difficulty in replacing the stone used in the base, and he gave the assurance that the .stability of the building was not in tho slightest ricpree ntfected (for the reasons above stated) by tho cracks discovered in the base. Before it was erected, representations liacl been made that the stone specified was not exactly suitable, but nothing had come of them.