The Opbra. — Saturday was a "Command' night by his Excellency, at the Opera. The house was very fully attended, his Excellency and a large party from Government House be ing present. The opera performed was "II Trovatore," and the piece for to-night is "Maritana." — New Zealande'r, Nov. 21. The Gas Works.— The works are proceed ing rapidly, under the skilful and energetic management of the engineer, Mr. Wark. The well ii now eight feet diameter, and upwards of 80 feet deep. At the extremity adjoining Nelson-street, the walls arc being erected of a house to be used either as a smith's shop, a workshop, or a store, if necessary. At the other extremity of the ground thers will be another house erected shortly, of wood, which will serve as an office for the Gas Company ; and also contain the " governor"— ■ machine for regulating the supply of gas to the town. Each gasholder is estimated to hold about 31,400 cubic feet, or 800,000 gallons of water, Besides this the interval between the vessel and the brickwork will contain 50\'000 gallons more. The expense of constructing each gas holder, by contract, would have amounted to about £6000 ; the present expenses, however, will be much less, owing to the judicious management of the engineer in using materials to be obtained on the spot. The internal diameter of the pipe, for the outlet of the gas to the pipes 1o supply the town, is 12 inches. A vast amount of labor haS been Expended [n excavating the" stone, which has been vied in building the outer wall around the gasholders. Some of the stone being soft has supplied the, sand used in mixing the mortar. The engineen to the Gas Company is constantly on the ground, supervising the progress of the works ; he is entitled to great credit for the able design and workmanlike execution of the whole. — Ibid, Nov. 19. The Minerals of Nbw Zealand.— Dr. Julius Haast, Provincial Geologist of Canter-* bury, gives a list of the collection already made for the illustration of the different branches of natural history, as well as for the instruction of the public generally, if only the. necessary accommodation could be procured for their display. 