Tonga Bay Granite.

Progress, Volume III, Issue 9, 1 July 1908, Page 298

Tonga Bay Granite.

A New Zealand granite obtained from Tonga Bay, about 30 miles from Nelson, is being used in trie construction of the new Public Trust buildings at the corner of I amb- vton quay and Stout street. As this building is the first in which this stone has been extensively used, special interest is taken in it, and it is satisfactory to note that the stone is a first class building stone, being entirely free from flaws. The stone can be obtained in blocks of any size, a number of stones in the Piiblic Trust building weighing upwards of five tons, and some even reaching eight tons in weight. The difficulties and obstacles invariably met with in opening a new quarry have all now been got over, and J. and A. Wilson, limited, who found it necessary to purchase the quarries and plant from the Tonga Bay Granite Company, are now in a position to supply granite in any quantity. An interesting article on the stone will appear in our next number, with illustrations of the building, and also some views of the quarry. Tonga Bay granite is a stone easily worked and looks well in any finish such as rock faced, fine axed, and can also be polished. It is also a first class stone for carving and it no doubt will be largely used for monumental work. 41 There are at present 30 masons engaged at the Public Trust Buildings

Iv \ recent issue of the Revue Snevtifiqne Dr. C. Ff ry gives an illustrated account of the new methods of determining high temperatures in industrial operations. For temperatures up to 700 deg. C. he recommends a thermo-electric couple of lronconstantan, from that to 1300 deg. C. one of platinum and its alloys, in each case in combination with a self-registering arrangement Where the thermocouple would be injured if brought into direct contact with the source of heat, he advocates the use of his own pyrometer, in which the radiation from the source is concentrated by a concav e mirror on to the thermo junction. For sources of small dimensions at temperatures above 900 deg. C, optical pyrometers, t.s., Warmer's, are the most useful.