THE CAWTHRON INSTITUTE.

Press, Volume LVIII, Issue 17470, 2 June 1922, Page 5

THE CAWTHRON INSTITUTE.

INSPECTION OF THE WORK. (special to "the pbess."} NELSON, June 1. The value of the Cawthron Institute of scientific research was indicated by the work seen in progress on the day of public inspection to commemorate the anniversary of Mr Cawthron's birthday. In the chemical laboratory, which is under the direction of Mr Rigg, niueh interest was shown in the map which epitomises the results of the soil survey of the district, and in the conclusions which had been reached by experiments on the suitability of _ the i different types of soils for various ! classes of crops. Not less interesting i t6 many visitors was a map showing : the distribution of limestones, suitable ! for agricultural requirements, in the ' Nelson province. The experimental work I carried on in the laboratory was also j followed with great attention. The methods for the chemical and mechaniI cal analysis of soils and for determinI ing their lime requirements were all in 1 progress, besides such physical experij ments as the demonstration of therela- • tive capillarity of different soils and ; their power of absorbing different food constituents from solution. Ex- ! periments were also in progress on the composition of different varieties of i apples grown on the different orchard i soils of the district, j In the entomological division in charge of Dt. Tillyard there was exhibited an interesting collection of beneficial and injunous insects of various kinds. In a large case was a representative collection of New Zealand and Australian orthoptera, including formidable-looking wetas, king crickets, cave wetas ( stick insects, mantis, and various kinds of grasshoppers. Another case showed the life history of the Australian moth, lacei win?, an enemy of grass-grubs, while a third exhibited the various kinds of ladybirds introduced into New Zealand to combat s'alo and aphis pests. • A specimen of the parasite of the woolly aphis, aphelinus mali, was shown under I the microscope, while under another ! was to be seen a mounted specimen of a fairy fly, a microscopic insect which parasites the eggs of leaf hoppers. The cage used for rearing aphelinus was also shown. An exhibit of the life history of the New Zealand sandfly showed the larvae and pupae in position attached to leaves of watercress under water. Other exhibits were the sheep-tick, which is really a fly which has lost its wings and taken to a parasitic habit on the sheep, various species of hover-flies, useful because their larvai feed upon aphids, the European drone-fly, often mistaken for a bee, but quite harmless, and of value in crosspollinating flowers, and some fine flower wasps from America, which attack grass-grubs. In the plant disease laboratory methods of study and examination of fungoid and bacteriological diseases were explained by Dr. Kathleen Curtis. The demonstration was illustrated by samples of black rot, brown rot, and fireblight on fruit trees, rusts on cereals, grasses and clovers, leaf spot fungi on vegetables, and club-root fungi on swedes. Non-parasitic fungi were illustrated by dead-wood and ground fungi, the latter including poisonous and edible species. Bacterial diseases were further illustrated by gall formation on hop roots, a serious disease in some localities. In the photographic room demonstrations were given by Mr Davies in the preparation of micro-photographs, and also in the preparation of enlargements and lantern slides, and the quickness and certainty . with which excellent photographs were taken, developed, and printed must have been a source of envy to many amateur photographers. ' In the museum few visitors tailed to find much to interest them. The Marsden collection of china and pictures always attracts attention. Samples of Onakaka iron ore, the pig iron prepared from it, and turned castings, together with examples of Scotch pig and high-class wrought iron, called forth a number of enquiries as to the' metho'ds of preparation from the ore and the relation of steel to cast and wrought iron. It is intended to considerably amplify the technological branch of the museum, which includes minerals of economic value, mineral oils from different districts in New Zealand, with some of the products obtained from them, and photographs and other exhibits demonstrating the relative fertility of various soils, and tho effect of different methods of cultivation upon them. The museum also includes a very beautiful collection of tropical insects.