DR. HECTOR'S REPORT ON BUILDING STONE.

Otago Daily Times, Issue 238, 24 September 1862, Page 5

DR. HECTOR'S REPORT ON BUILDING STONE.

Dunedin, 22ml September, 18G2. Sir, —I havo the honor to furnish you with the results of an examination of the sample of building stone, which was forwarded to me for an opinion from the Provincial Engineer, with your memo, of the 7th instant.

Although to the eye it appears to bo oven superior to most other* in the province, especially if judged by the texture of the dressed face, it is really of very inferior quality, tv it nb>ovba water greedily, becoming friable, nntl tolling to sand. Moreover, it contains a notable quantity of deliquiaeeut alkaline salts, which must constantly attract moisture from the atmosphere, and powerfully assist the process of disintegration.

U used at all as a building material, it must be very carefully dressed, and not placed in positions where it. would Iw exposed to beathip rains, it might, ! however, be suitable for interior work, although it would always Lo a damp and friable s.tonc. It has been formed of materials derived from the ancient schists of the Horse Range*, and is geologically probably of upper secondary or lower tertiary age. By the analysis which follows, it will be seen that it is only one-half composed of durable sandy matter, while the remainder is' of an earthy nature, tot-illy dftiicienfc in lime, which, if it had been present, might have eement«-d the stone on exposure to the air. When soaked in a solntion of sulphate of soda, and suspended until the eaU. i» crystalized in the manner recommended for the purpose of imitating the action of frost on a ttone, it rapidly exfoliated, and fell to sand in the e<mn-c of a few days. I have the honor to be, Sir, Your most obedient servant, (Syned) James llkctok, -Provincial Geologist. To his Honor, tie Superintendent.