MICROSCOPE IN TRADE.

Hauraki Plains Gazette, Volume XXXVI, Issue 4871, 31 August 1925, Page 4

MICROSCOPE IN TRADE.

ITS VALUE TO TRADERS. UNMASKING DECEPTION. How deception in trading can be unmasked by means of the microscope was the subject of an interesting lecture before the Hamilton Rotary Club by Professor J- C. SperriirJohnson, professor biology, Auckland. The microscope, he said, had long been used as a fascinating hobby, and also as a highly practical application in the study and cure of diseaise, in bacteriology, identification of crime, and study of the structure of rocks. Galileo, the famous astronomer, made a microscope early in the seventeenth century,-’and from these crude beginnings microscopy has been marvellously expanded, and the structure of the modern microscope in itself, both in connection with metal and lenses, was a marvel of technology. The professor went bn to describe one of its many uses, rather overlooked by the business community. The average businessman, he said, tended to be conservative in many ways in that he was slow to seek the advice of experts on matters about which he was ignorant, and by failing to delve into the closer technicalities of his calling. This was not so marked in New Zealand, where, generally, he had found a great eagerness for knowledge by men employed in business. The services, of the trained microscopist was, however, almost indispensable to' forms of trading, for it was he wlio brought deception in the quality of goods to light and revealed by the aid of his microscope the many adulterations to be found in modern articles of clothing, food, and other materials of general use. The prbfes-

or showed how, by means of the mic■oscope, the composition of textile joods could be definitely ascertained; iow pure woollen garments could be lompared with mixtures of wool, coton, and other fibres. This wais aciomplished by separating the strand's >f the material and closely inspecting herii by a proper adjustment and by neans of proper light, with the microscope. The trained microscopist :ould detect immediately which were he woollen strands and which were he foreign ones. Tne isame with real irtificial silks. The difference here vas that artificial silk, while a wonlerful scientific achievement, which •esembled real silk very closely, was •ct lacking in one element which the ’eal-silk possessed—a delicate vanish which was applied to the threads if the genuine article by the silkrorm, and which (science had, so far "ailed to reproduce in the artificial. \nd so with foods, which were subject o considerable adulteration, could lie composition be determined by the irimafy shape and qualities, which vere retained even though subjected :o various, processes of manufacture, lams, for instance, were a food which iffered opportunities for considerable idulteration. An American scientist lad classified jam into two groups—sophisticated jam, which had other ■ngredients than" the buyer would expect from an examination of the label,

and the unsophisticated or pure article. Marmalade was often not liecessaily composed of oranges, but chiefly of mangel wuszels, with orange peel and artiflcilil pips added. • In Liverpool there used to exist a vocation for the making of artificial piixs for jam. A minute shaving of these wooden pips under the microscope, however, would show the elements characteristic of a fruit structure. Oases had been known of artificial peppers being made of pressed powders, coloured to imitate the real peppers ; also pellets of paper were coloured and moulded to represent pepper berries, but the latter, when placed in water, would disintegrate, and further testps could be made of the residue. The professor briefly referred to the adhesive quality of the best face powder, this being due tc. the minute dimension of the starch, which formed the main ingredient. Inc i dentally, starch from different sources could be differentiated by the shape and size of the grains.. For example, potato starch, which was an adulterant for real arrowroot, could thus- be detected. The address was generally accorded to have been one of the most crisp and interesting delivered before the Hamilton club, and the professor was accorded a hearty vote of thanks.