CHEMISTRY FOR THE G0LDFIELDS.

Waikato Times, Volume XXVI, Issue 2137, 20 March 1886, Page 4

CHEMISTRY FOR THE GOLDFIELDS.

Tiik following (irjtico of Professor Bhck's hook, with the above title, appears in the Tuapeku Tim, h :— _ _ 'The autlior ayts forth in the preface his objects in writing the books, the fiist, a»<l, pTiiapss, also the most important, being "to put into the hands of mincis and pnfcpeoton a guide t;o enable them to identify, by simple test-i •m<l clitap appliances, the valuable ore* when they ii'i'l tliun. Hie book conrne'iJCiM with tbj*v< ry A l> C of clit mistiy— ii < \pl in ■ t 10-i in ti • m 11 [»l -t u i tii-. ot llic ♦<.•< lime.il dill'-iuic • between el< vi' ut^, na\ tines uid comp'Ximh, de^ciihmg generally tn« kifws ot tlu- elements, both lion m.italho .mil tin im,t«l . An is a mutuiuot oxygen, mtiogeu, uaiboniu acid, a. id watu, •m>l tint it h not a coinjtound is proved by the fact th.it each iugrcdjent behaves exactly according to iM properties, just as when separate. In atmosphoric air tliere are about two tons of oxygen gas resting upon every square yard of surface all round the globe ; in fuck, looking at the earth and its constituents, so far as they Are known to us, we find that oxygen comprises abbut~4S p^r cent, says the author, of all the matter with which \ta are adquainted. The existence of oxygen was unknown uiifiP'4-iO tyenrs ago, whro it was dig. covered by Priestly, an English clergyman, and almost at the same by Seheele, a Swedish chemist. Of the old alchemists, Dr. Black says: "These enthusiasts— the pioneers of the chemistry of to-day — were <larkly reaching after mysteries, the key to which lay in the troe interpretation of the phenomena of the fires they employed in their roastings, fusions, sublimations, and distillations." The nature and pioperties of oxygen ar<j explained, and a list of the oxides and salts formed by combination witili'ft is given, The modiliefiHoj of oxygffi, known as o^one, with it^ in'-onsi-ft'u'l pmpei ties, is describi'd, And nijtiuctioqa .given as to the best methods of testing for its presence and of preparing it. All the non-metals arc tieated as exhai^jtivoly a? oxygen; they arc carbon, hyUvogen, nitrogen (with a.nmonia), and the, halogens or salt-makers— chloiine, bromine, and iodine— with sulphur, pi««phopu8 r boron, and silicon-. The value., preparation, t and uses of sulfJliuWttiid hydrogen (rotten eggs gap), also sulphuric acidj and tHe nature of the phenomenon known as ign\a fotinif, or " Will o' the Wisp/ are all dwelt upon interestingly. The following abont phosphorus is charmingly readable :—: — "It was not till 1770 that phosphorus wa^ discovered to be a constituent of bones. It had been made in small quantities from other animal sources before that time, but wa3 regarded only as a chemical curiosity. Its first discovery was like many other important discovdic3, accidental. A Get man alchemist stumbled ,on it while distilling a mixture of sand and sonic animal lesidue which he wi«j.toi>turin££ in tin: expectation of finding a liquid that would turn silver into gold. Afte r Sulieelu's discovery of a pro cess for cxtiacting it fiom bones, it soon beScame unheisally known." There is jtfeuty more in a similar strain all through the book ; and ever and anon the Professor's dry humour may be recognised by those who know him, in such passages as- the following about sulphur : — •* It played an iinpoitant paitin the alchemy of the middle nge«, and our forefathers held it in considerable reaped under the ( name of brimstone " The second part df the book, from page 243 to the end, refers to metals, ores, and processes of importance to the miner. Lime in all its forms ia dealt with ; the other metals of $he alkaline earths ; also metals of the nlkalfs, except c;e3ium, rubidium, and lithium, these latter not being of importance to the miner, being passed over ; qucj then the inagncaium group, in which is" the 'metal, zinc. An important ore or zinc is> blftnde, or zinc blendo, known as "Blackjack" by the miners. It contains, when pmc, G7 per cent of the metal; haidpis-s, 3 h to 4: specific giavity, 3 9 to 4; lustre, re-inous or waxy ; colour, usually bi own, l>ufc ranges from yellowt.h v. hitu thiough vanous sliades u\) to brownish black. The bkc^tintsaie due. to sulphide of iiou. 'Jfllopowtier is white, greyish white, or oceaeiotiAlly.' light reddish bro.vn. The ore is br-ttlc. The statement is made that a large>jnantity ot zinc is u->ed in making gatvanifeed iron, and then the Professor proceeds to desctibe the method of applying the zinc to the it on ; the various uses of zinc are all fully told— for making brass, in galvanic batteries, also as a component of white paint— then the tests, or means of detecting the metal, are given for the benefit of prospectors and others. We are told that "it has been found in Fmall quantity in the Ka^koura Valley, at Itosg, Reef ton, and' on thfi coldfidlds of tlie West Coast widely dismnrifcedi; and that "the Rangitoto silver ore contains it." About galena, one of the ores of lead, the author spates '"that the samples of the ore from Te Aroha, in Auckland, vrevo found to contain sul phides of zinc, copper and iion, aud 2.J ounces of gold and o.iO ounces of silver per ton. G.deu.i, like most sulphides, is a cause of gieat tiouble in the gold bearing qtnit/, as it flours the mercury when gfOttnd with it, sometimes producing a mixture that remble.3 a true amalgam, but contains very little gold." The method of sepaiating the silver, lead, and gold ftom galena by cirpcllation is fully explained. The process discovered by Mr Pattinson. of Newcastle, for the improvement of lead by the removal of the silver is given in detail, an extract from the valuable repoit of Air H. A. Gordon "to the New Zealand Governmeat onthe Australian Goltlfields, 1885," being embodied in the description. The following is taken from the chapter referring to copper ' ore :— " It occurs of good quality in No* Zealand, at several points on the West Const of the Middle Island, especially near Hokirtka and the Haast/River, in the province of Nelson, and 'in the Wakatjpii, Carrick, and Waipori distucts of Otago, as well as in some parts of the Noith Island." For Copper pros hoth the quantitative and qualitative analysis aic given, in order that the prospector, or amateur chemist, niay be able to ascertain the percentage of metal in the oies. Of all the chapters in the book, however— which is well worthy ot diligent study throughout, on the part, not only of linnets and prospectors, but of all classes in tho community the clmpteis referring to silver, iron, ■ a,ndpold arc probably tho most interesting, to us hi this di.stiict. Sixty-thiee pages of tho book aie devoted to a desoviptiouand study of all that relates to gold. The lemaiks on gold have reference to its geological position, how (fuartz-rcefs were fonnid, how gold came into the loefs and into the dntts, testinc ami assaying gold-bearing ores ans bullion, quantitative testing, assaying, tho chemistry of gold-saving processes, the manufacture ot sodium amalgam to rectify tho "flouring" the mercury, amalgamating the copper tables, treatipeut of p> rites and other gold-bearing inctallic sulphides, and the propel tie's a[nd .compounds of gold. The author recommend •> tho study by mining nifuuigeteof Afred G. Lock's woik on "Gold : Its occuirence and txtuiction, ISS2," An appendix* contains a number of tables and Kiiemcj ioi ti?tinj» ores anil solu tions of metal; also an aiticle by Mr Alexandcf Af.A., on tlio use of the blowpipe for the tame piupose. The book is thoroughly inteiestiLg and instructive throughout, and i^ wutten with tho ckaruess only posailde from a complete knowledge of the sub-

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