THE CYANIDE PATENT.

New Zealand Herald, Volume XXXIV, Issue 10416, 14 April 1897, Page 5

THE CYANIDE PATENT.

HEARING OF THE APPEAL CASE. [BY IELKGRAFH,—OWtf COKRESFOSDENT.] Wellington, Tuesday. The hearing of the Cassel Company's appeal against the decision of the Patent Olßcor, who refused an application of the company to ameud the specification of the cyanide process, was resumed this morning, before Mr. Justice Edwards.

Professor Black handed in tables of experimental results with cyanide upon different kinds of ore. He described also the different processes of " leaching.' and the practice on the New Zealand goldflelds. 1" reply to questions by Mr. Button, he said lie had not met with any authorities showing that cyanogen would dissolve gold. Sir Robert Stout handed in the notices, decisions, and minutes of proceedings in connection with the patent for extracting gold by the cyanide process. Mr. Buttou, in opening the case for the respondents paid that the evidence already given went to show that long before tins patent it was known that cyanide would dissolve gold. It was a matter ot common knowledge. The claim with which the present proceedings were concerned arose from a pretended patent for a particular process. The English patent obtained by the Cassel Company treated ores by strongsolutlons of cyanide. Apparently it was not known to them that weak solutions were followed by better results. The only way of getting at the proportions which would be efficacious was by analysis and experiment. It was easier to find out the true proportions by ordinary experiment than if the specification of the patent had to be worked by any other than an expert. Saving gold by cyanide was nothing new. It was not even the best or most rapid solvent of gold. Chlorine Was much swifter in ita operation. The appellants had obtained a patent upon general grounds in England, and they found it to be vaguo. The object they had in view was to substitute lor a general patent which was vague, ft patent upon particular grounds in New Zealand. They looked to this expedient to clear up what was defective, and make a vague claim good. The practice of leaohing was as well known boforo the Oassel Company obtained their patent as after. There was nothing now in it. Nothing new was brought into existence either in respect to cyanide or tlie system of leaching. Mr. Skey, Government analyst, was the first witness called to-day. Ho said tho English patent contained much more information than the New Zoaland patent. Any ordinary person would not be able to work the specification for this patent. Hβ had known by experiment the effect of cyanide ou Rohl long before the patent. From a half to two per cent, was tho most effective proportion of cyanide solution. Chlorine was eighteen times moro rapid in its effects upon gold as a solvent. Cyanide had greater attraction for gold and silver than it had for the baser metals. Cyanogen had little or no effect on gold. There were two kinds of analysis, the volume metric and the gravometrio. He would apply the gravo-metrio in respect to gold ore. The witness was exiimined at. great length by Sir R. Stout upon tho specih'cation-as to whether it provided for cyanogen, or something which produced oyano'iion, in order to work the patent. Mr. J. Parks, M.M.1., London, an expert in mining ohemistry, said he was attached to the geological survey, and had reported from time to time on the mines and mineral deposits in various parts of the colony. Looking at this specification, he did not think it could bo easily worked by ordinary experience. It was too vague. He did not know any place where cyanogen was worked. The information in this New Zealand specification was not sufficient. The numerical parts wore not specified. Above and below a certain strength tho results diminished. Iα the English patent there was no reference to " dilute solution." The proportionsof cyanide of potassium to be used were known, but there was no such knowledge as to cyanogen, Cross-examined by Sir Robert Stout, witness said that a large cyanide plant was being obtained for the Anglo-Continental Company. Hβ did not know that cyanogen was to be employed. Cyanogen was almo3t useless as a solvent, ami thorefore would not be employed. Witness had no experience of strong solutions. Ho had made many experiments in his own laboratory. His experience was that the effect of oyanogeu upon gold was very feeble. It was also a most dangerous gas. Clement Dickson, battery mauager of the Waihi-Silverton mine, had been battery manager at the Kleinfontein mine. South Africa. He learned chemistry in the Auckland College and tarnecl the whole of the evanide process in Africa. He could not work under the New Zealand specifications. It did not give sufficient information. One would havo to make experiments to determine the proportions of cyanide to the ores for himself. In cross-examination witness said ho ouly knew anything of cyanide when in South Africa. He was there only two yenrs. Henry F. Shepherd, battery superintendent to the Hauraki Associated Gold Reefs Company, deposed that he could not form any idea of the method of using cyanogen from the New Zealand specifications. Any person reading them would still have to rely on experiment. The cyanide process was of no use for some ores—the Monowai ore for instance. He had experimented with cyanogen, but its effect was very feeble. Counsel's addresses are to be heard tomorrow. ___^^________