THE AUCKLAND INSTITUTE AND GOLD-SAVING.

Daily Southern Cross, Volume XXIV, Issue 3509, 14 October 1868, Page 4

THE AUCKLAND INSTITUTE AND GOLD-SAVING.

To the Editor of the Daily Soutukrn Cross. Sir, — It was with much pleasure that I read your rej orfc of the kvt meetu.g of the Auckland institute. Mr. Whitaker's statement, thit the me of one kind of water had pioduced abjub double the quantity of gold that CDuld be ob^ai icd by the use of another kind of water, U a retra-ka.>le one. ami the subject well worthy of investigitiou. Dr. Fischer's idea of zinc plates placed ov«r the water, just touching, the surface, so as to catch the fl mating gold, is no new onp, a3 I have heaid the ma'.ter frequency discuised. In fact, for thit purpos-*, copp3r cylinders are greatly pnferr d, as being more easily kept clean. That method, however, has been already tried at the Thaoae*, and abandon; d. Dr. l'urchas'd ideas of amalgamation and oth-r matters are Certainly very antiquated. That learned gentleman has evidently been reading some of Dr. Qre'a old editions, treating on t'»e a-naljamatiou of silver, and aa Captain Hutb'ni told him n«t a!; all .suited for the requirements at the Thames. All matters at the Thames connected with mining and quaitz-crushing will apeedily find their own level, but nothing short of actual experience on the field is capable of effecting thi--, ai every looihty hasjts own peculiarities to be studied, and cheimc."" obstructions to be overcome In Victoria, quartz is cheaply crushed, as the gold is generally coarse ; hence the crushing is coars- ly done. fu Ca'roruia vi much more finely crushed, and ,-b the Thiiu-a it evidently requires to ba crtijliud (iti»r than ether, on account of the fineness of the god to be exciauted. I quit? ag cc with the rcm.irk of Mr. Gillies that largo public oompani< « ar-j not always the best, as improvements are much moie like'y to be effeuted by a numerous body of men interested in the same pursuits th.tn by one or two men cicting as managers for large compiu.e- 1 . It has ben proposed by your contempoiary that deputations should be sent from the Thames to Victoria for the purpose of seeing how things are done there. 'Ihey might as well send over a deputation of printer.* from the Herald office for the purp se of seeing how the Australasian is jr'otel. It is amusing how "contrary" he cm be. He rails against gaol commissioners who inquire into the working of all g.tols in the colony ; and in the nexb brea'hadvocites a mining commission, lhe Victorian aud the Oaliforniau methods of saving gold are well known. 1 h«-r.j aiv m- ny Victorian as well aa Californi n dipg-rs at tlw Thames, and some of them are engine eis who have been all over the colonies, so that it matter, are badly minag< d he c it is not ft? want ol the kuowle 'gd of how things ate done ehe whi re ; but, as I have alrealy stated, each goldfield has it j own peculiar difficulties to b« overcome, and tli it both chemically and m^uhauically. Another matter I wish t > allude to, and that is, the fineness of the holes iv s*amper-box grating". We would naturally suppose that gratings having only sixteen holes to the square itch would be vcy much coarser than gntiugs having 400 holes to the f-quarj inch. It is not necessarily so, however, a«i the individual holes may all be dulY,! ir rather punched, by the same sized puncb, in b^<,u ctses necessitating the quartz to be Htim,«ed to the same fineness Le r ore it c uld escape through the gratings. In the former case the grating is strong, iv the latter weak ; [the one affording a slow, and the other a rapid, discharge from the stamper box. At Hawkeawood's foundry in Chapel street, a number of stamper b ixes are being made for Tapu, and, in order to allow a sulficient di-charge as we'l as strong and tin. ly-perforatecl grating?, the boxe3 have only two staui) ers each, at d open at the ends as well as the frji.t. a'l the gra'.mgs slopingoutwards, and a consi 'eralile spate to be left be f ;weei» each box when erected, thus giving a greater breadth of tible in proportion to tne iiiuii.j r of f-timperj than is done elsewhere. In al' cases, when speaking of gratings, it is desirable that a certain size of punch should be refene I to, and not the number of holes to the inch; thus, for instance, No 1 would represeut the coarsest punch used for gratings, No. 5 the medium, and No. 10 the finest used. Ihia anangeiueut would at a glance show tho fineness to which quartz required to be reduced before it could escape through the gratings, a thing which the statement of merely so many holes' to tlfe tquare inch fails to convey. — I am, &c , October 10, 1868. Dysamttb.