PROFESSOR BLACK IN OHINEMURI DISTRICT.

Te Aroha News, Volume III, Issue 130, 28 November 1885, Page 7

PROFESSOR BLACK IN OHINEMURI DISTRICT.

PRO?ESSOR BLACK reached Knran#ahake , on Mondiy last, and gnve the first of hi^ lectures in the Woodstock furnace house the same evening nearly 200 people being present, the great is»3°rity "i whom were inner* : many attending from ©wliaroa, < Waihi, and Waitektfuri. The Professor *pent the first couple of hours instructing his hearers how to test various minerals \,y what is termed the wet process ; after Which he delivered a lecture for aboi t an hour, his subject being two-fold in chariet»r, viz.: 1. How qmrte reefs wei*» formed ; 2. How gold, silver, etc., en»- c into the reefs. M Warden Ken rick was in the chair, and in introducing the lecturer to tho«e present, spoite of him in the most Battering teiias, and referred to the great benefits certain ti result from the instruction he would impart, .and urged the importance of every miner in the district availing himself to'the tullest possible extent.of the lectures. A most liberal supply of | tent tubes, chemicals, etc., were provided, to enable any present who felt «o incline 1 to take part in the testing of orea^- On Tuesday the Professor, pecompanied by Messrs Moore, Walsh, Humphreys, and Fenton visited Uwharoa and "Waihi (and appeared greatly pleased with the extent of apparently most valuable quartz bearing country passed through) returning to Karangabake same evening, and resumed the testing class and also his lecture. Wednesday was devoted to test ing samples of different ores by both the dry and wet processes, a large number of miners were present throughout the day, the Pr6f essor being assisted by Mr Fenton, who*took charge of the fire tests. A fire test 'from the Golden Point mine yielded at the rate of 131£ozs of silver and 2ozs 15dwts of gold per ton, and a teat from the main reef of the Sutro, 1807oz bullion per ton. Several te9ts from Waihi also gave satisfactory returns. The Prof easor spoke in high terms of the rich mineral resources" of thedistrnt Mr McLaren occupied the chair during the lecture on Wednesday evening. On the conclusion of his lecture the Professor expressed himself as being immensely pleaded with the attention shown by his tiearere, their aptitude to learn, the enthusiasm shown, and generally with his visit to Ka-angahake and'suriounding d'strictß, and urged upon all the necessity for following up the •work he had commenced amongst them, and improving their knowledge of chemistry. The Chairman followed with a <-apital speech, and referred to the advisability of' forming a class to continue the work. Mr T, Gavin, in his usual manly trad straightforward style, expressed the gratification it had afforded him and all present to listen to Dr Black, aiwl the de* airability of following «p the good work <>oinmeneed. A« a mining community, it ■was an absolute necessity for them f> know as much as possible respecting the industry by which they lived, and he ■would "propose " That they form Lheiuselves into a- branch of the Thames Scluro! of Mine-, to be called the Karangahake Branch," Tba resolution was sanded by Mr Wm. Morgan, and carried new con. Mr Alex. H<>gs n«xc p:oposed, and Mr F. Stmie seconded, "Th.it a Provisional Committee be appointed to obtain all ,ueee<3ar> inf >rmatkm relating to smi", and report to « pnh'ir me«tin<r The committee to comprise Measi* fcittlejoim, LLali, Br&wn, Gavin, Liddell, Kneebone, Stone, Morgan, lle'itum, Mcliiuvr, Smith, and the. mover." Carried. liesolveu, Tinit a public moetin.^ be convened at the earliest possible date, to receive the coimniltee's report ; tlie mover to be the convener of the meeting. Pro posed by Mr A. Hogg, and cirried with sieeiamation, "That a special vote of thanks be given the Hon. Mr Larnach for liis thoughtful and persevering efforts in, forwarding the mining industry, and in -re especially for sending a gentleman of Professor Black's ability amongst them; and 'that the Chairman transmit the Fame." The Chairman next proponed a liearty vote of thanks to Professor Bluck, and in doing so assured him he had won , the respect and esteem of «very resident in the district, etc., and spoke in eulogistic terms of the Proteseo/s abilities as a lecturct etc. Carried with acclamation. The rroteMs'r, in replying, thanked them all for the kindness and attention shown him since his arrival amongst them, etc. Votes of thanks were passed to the Chairman, to Mr K. K. Davis, for the use of , the iurnace^house, tables, .etc, and also to Messrs *Smith «nd Hcslett for the kind assistance they had given liiia. The Professor, (accompanied by Mr Fenton, left for Thames on Thursday morning, and was succeeded by Mr Montgomery "same day. For the benefit of those who attended Professor Black's lectures at Karangahake and who may attend his lectures at WaioTOngoufai, particulars respecting numerous tests conducted by him are Usrewith appeuded: — Liquid Testing. Tests for silver. — Take a glass test tube and pour in from the glass of silver iij, solution to a depth of about, half an inch ; into this pour four or five drops of muriatic -aci<i', which will cause a white precipitate to form. To find ont which of these .three you are dealing with, empty out three- fourths of what is r in the test tu'ue and fill up the tube with aJtutnonja ; in the case of silver the result' mil Utf to" came the wliite ptecipi-

tatejt.Q disappear ami ~all -become -clear" ttffftin, and by .-.uuh a/e3HUfol|owingy^ may rVstj&iired\U? 'k!]»li v ? £'/u/ u lt !f dealing with. To be more fully satisoirtliisjmiitf y/Mi^ah jiro^e it as follows :-'^vfe ji'li^iiin'ieyiiia into i^ pour a portion of 'what' you" lmd pro viously euipti-u" out (wheu about, to a^d, tho ammonia) amT to it mhl a T^v, ufops of chrome, tlie lesult will bo to cause a, dark red. precipitate continuing tlio fact j that it is silver you are dealing with, as it always so.acts. , , Tests for Lead. — Pour, as in first case, a small quantity of the leal in solution into a glass test tube, and add a few drops of muriatic acid ; tho result will be to cause a white procipitate as in the case of the silver. Pour out a? before about three- fourths into another tube, and to what is left add a few drops of ammonia ; in this case the white precipitate will not dissolve or disappear, whereby ~ou may know it is lead you are testing. " To be further satisfiec? on this point you can prove it as follows : Take cjome more of the lead sblution, as at the first, and add a few drops of chrome, this will cause the liqui I to all turn the well-known yellow tinge of chrome. A third test for lead is by taking: a fresh ruaiitity of the lead solution, and putting a small quantity as at first into a fresh tube, add a few drops of iodide of potassium, in this instance, also, if what you are testing is lead it will cause a deep yellow shade. This last is a grand test for lead. Tests for Mercury (lower salts.) — Pour a small quantity of the mercury in solution into a glass test tube as in previous cases, and add muriatic acid as before, and a white precipitate is formed (as in the cases of silver and lead). Now aid a few drops of ammonia and tue solution becomes black, whereby yon mny know it is mercury, lieai in mind tue three minerals in solution already mentioned, viz., silver, lead, and mercury, are the xm\j three which, on the addition of muriatic acid, will form a white precipitate, and these three minerals cau all be testel with mari.-itic acid and ammonia ; the wnile precipitate occasioned in each instance by the addition of muriatic acid being invariably cleared away by the further addition of antmonia in the case of silver, remaining white by the addition of ammonia in the case of lead, and turning black where ammonia is added in the case <>f mercury. Mercury (higher salts). — Take a small quantity in solution in a test tube as before, and add a few drops of muriatic acid, in this case no change is occasioned ; a<ld a few drops of sulphurekted hydrogen, and the result will be to cause the solution to turn brown and then black. Another test for mercury — higher salts — is to add to a small portion of tho solution two or three drops of potassic iodide (*.«., iodide of potash), which will cause the solution to turn a fine red precipitate j and by emptying out three-fourths of this froii the tube and adding more potassic iodide to what is left, it will cause it to become quite clear again. Tests for Gold.— Fill two glass test tubes to the depth of about an inch with the gold in solution ; to one of these add a couple of drops of muriatic acid and no change follows, further add a few drops of sulphuretted hydrogen, and the liquid will turn black. In the case of the second test, add to the gold solution two or three drops of sulphate of iron (the Professor here showed his hearers a quantity of sulphate of iron in a <lry state, in the form of green crystals, ami generally known as copperas), and the solution will bo turned to what appeared when held beyond a light, alight brown, but if held between one and the light it appeared as of a light green colour. Special points to remember with respect to gold. — In solution it looks light yellow, li on the addition of muriatic acid no ct angc is occasioned it will prove conclusively tliat neither silver or li'sid is {> reseu i ; and if on adding .su! p. i ate of iron the browu tinge becomes apparent, it is ceituiu t*ie solution is goli. If no sulphate of iron at any time is attainable use instead oxalic acid, as it will do equally well. Metals dealt with known as iron group, viz : 1. Iron (higher ssilts) ; 2. Iron (lower salts) ; 3. Nickel ; 4. Cobalt ; 5. Manganese ; G. Zinc ; 7. Aluminum. Manganese. — Take a small quantity of the solution as in former cases in a test tube, and a<ld a few drops of muriatic acid ; this causes 'no apparent change to take place, therefore take a fresh test, and this time add ammonia sulphide, and the solution is turned to a kind of bilious skin colour. Another test : Take a small quantity of the solution as at first and add to it its own bulk of caustic potash, this will first turn the solution a cream colour, which on being well shaken, and fresh air admitted two or three times will grt dually change to brown, and finally become quite black. The Professor here remarked he had never seen a district with more black oxide of manganese existing, than Karangahake, it was present in amazing quantities. Another test, viz : Thefusion or Jlre test.- Into a little china cup (such as mentioned in making silver solution) put as much powdered saltpetre as would lie on a shilling! and also a small lump of caustic potash (say about the size of a pea if: have not got caustic potash common washing soda will do), next add five or six drops of the manganese solution, and ; placing the cup over a spirit lamp, let it boil down, an 4 if the solutionf be 'manganese,' , theinside.'of the cup and residue,, at tue * bottom' will be a fine dark green/* '" " Iron (higher salts). — Take a ir small,j quantity in a test tube and add 7 two or three drops of niuiiatic -acU ; no af par-

■ent-w!an^^esultTiVg--.3Afnuua>raittjaitii4t -neither silver., leal, <>r-J>vM'X- i^ P- l'fhylroi^n, with the only rosult t at tile solution is|lunicJ'MHiuiNVMat*n|i!|y^"<)jc!ng us -to cordui'loi'Ba^ipiujd'll'y sulr; j)huf*iii thlsulplmi'eUc/l hym-wgoir) but no white proeipitato.is forme I. Uemnni Her 'tlinV ;»*!£ ' tlie , iiif tic-rate i^ solution Seated /previously (i.e 1 , before cbmmeiicing on those termed the Iron Group,) on the-additioirof- sulrliuretted hydrogen gave a wliit3 , pmeipitate ; bnt this does not, and the same mny bo said t of all tlrs group. Another test : T ) fl small quantity of the solution add its own bulk of sulphide of, ammonia, and the result will , be a pure black precipitate, showing thatthe solution must bo either' iron, nickel, or cobalt. Now if- it, be iron, the addition of muriatic acid will cause the; solution to become quite .clear again. But there are two kinds of iron salts (higher and lower) and it is necessary to know which is being dealt with, and to prove this take a fresh test and add about its own bulk of ammonia and it will turn a foxy brown thin jelly, showing it is higher salt irou ; the brown jelly - like substance being really iron rust, combined with wat n r. Another test : Add to the solution its own bulk of sulphocynnide, no precipitate will result, but the solution will bo j turned to a dark red colour. Another test : To a fresh quantity of the solution add two or three drops of red prussiate, and the result will be to turn it a greenish brown colour (not blue). How the Foregoing Knowledge may he applie I by the Miner. — Galena ore (galena contains 207 parts of lead and 32 of sulphur, and always carries silver.) Take a lump of galena atoue, break off a small piece and pound it up in a mortar to a fine powder Next put this powder into a en cible, add ,niJ*i<tei»qM^ and boil it over a lamp ; this will cause the sulphur to become detached, arid leave the taad in solution in the bottom of the crucible, and by fiUeriug tbis ' through a blotting-paper funnel (note — never use same piece of blotting-paper twice), the lead solution will bs obtained as will be proved on the application, of the test already referred to. Cinnabar. — This is a heavy, red stone (and the more it is pulverised the darker the colour will become). Break off a small piece as before, and when reduced in the raortar to a very fine powder, turn it into a crncible and boil it down to dryness iv a liquid called aqua regae ] (which is made by mixing one part of strong nitric acid with three parts of strong muriatic acid) the residue will be corrosive sublimate. Disso've the dry residue in water, and to the solution apply the tests for mercury (higher salts). In every 2321bs of "cinnabar there are 200lbs of mercury and 821bs of sulphur. Silver. — Take some of the ore and very finely pulverise, put a little of it into a little china cup (such as made for this special purpose) and add nitric acid (the acid must be strong, and smoke when the stopper is taken out) and then boil over a spirit lamp, keeping the mixture well stirred with a glass rod. (Note: The brown fumes that will be thrown off at this stage 9bould be avoided, being highly poisonous, also if any of the acid should be spilt on the hands, they should at once be washed in water, as tLe acid will burn the, flesh if allowM to remain) ; when boiled nearly to drynoss, add a little more nitric acid, and further boil, until nearly dry ; next fill np the cup with water, stir well with the rod, and filter through blottingpaper, placed in a funnel ; the solutic n resulting will contain the silver if there, is any in the stone. Remember the articles used must be perfectly clean, and if the solution at first be not quite clear, filter it again till it is so. The foregoing directions will apj^ly to all thej silver ores of this district, viz., sulphide I of silver, but would not autfiee lor the main bnlk of Australian silver ore, whore the metal is principally faun 1 ii> t ie form ot chloride, chromi le, or iodide of silver. Having obtained the solution dirert fr«>,n die ore, now carry out the instrurtioiis already given for testing silver by adding muriatic acid, and the \yinte precipitate resulting from this treatment will at once dissolve, anl clear up on the further addition of ammonia, if it be silver. {Should a brown jelly-like sub- ! stance remain after the disappearance of the white precipitate, it will prove the existence of iron iv the ore.