SCIENCE SIFTINGS

New Zealand Tablet, 30 March 1922, Page 46

SCIENCE SIFTINGS

========== By "VOLT” p~- I

A PRIEST SCIENTEST HONORED. In apparent silence important scientific works are daily being wrought at the Vatican Observatory. A few of these, as* the chart of the heavens and the photographic catalogue of the same, are known only in part by the public. Recently another volume has been published, the fruit of ten years of work of the illustrious director of the Observatory (Father Hagen, S.J.). The preceding publications of this scientist have already been .noted as the accomplishments of one profoundly intimate with the problems of the various constellations. The new publication constitutes a precious contribution and a magnificent guide for this important branch of astronomy. The celebrated University at Bonn, which was the cradle of these new studies, and where 50 years ago, Father Hagen began his scientific career, recognising all the merit of the new work, has conferred on the illustrious astronomer and director of the Vatican Observatory the title of “Doctor honoris causa.” The notice of the honor thus conferred on Father Hagen will be received with great satisfaction by many who know the modest and profoundly studious man who has become the splendor of the Vatican Observatory. MAKING CUPS AND SAUCERS. Everyone knows that pottery is made from clay, but many people will be surprised to learn of the other materials used (writes “A Potter” in a London paper). Ordinary earthenware is made from Cornish china clay, ball clay from Devon or Dorset, flints obtained from the seashore in the neighborhood of Dieppe, in Northern France, and “china” or “Cornish” stone. The delicate and more expensive chinaware is made from china clay, stone, and ground calcined bone, most of which comes from South America. The clays are churned up with water until a cream, or “slip,” of the correct consistency is obtained. The other materials are made into slips by grinding with water, and then the correct quantities of each slip are thoroughly mixed together. The whole is then pumped into a filter press, where the clayey mixture is retained while the water flows away. This mixture, still referred to as “clay,” is now ready for the making shops. Let us watch the earthenware cups being made. The first requirement is a mould, made of plaster of Paris, the inside of which is the exact shape of, but larger than, a finished cup without a handle.

A piece of clay, which has previously been evenly flattened out, is placed in the mould, which is revolved while a tool is lowered inside to shape the clay to the side of the mould. When finished, the mould is put into a dryingroom, where moisture is withdrawn from the clay, which shrinks and easily comes out of the mould.

The handle is made separately in another mould, and when it is dry it is stuck on the cup by means of a little slip.

In another part of the room, saucers are being made in a similar way. The top of the saucer mould is the shape of the inside of the saucer, and the tool which shapes the clay to the mould also raises the foot, or rim, on which the saucer stands. Once they are dry, our cups and saucers are ready to be baked, or “fired,” as the potter calls it. . This is done in an oven like a huge ginger-beer bottle, which holds some tons of ware. To protect the ware from the flames it is placed inside large-fireclay boxes, known as “saggers.” When the oven is full of saggers the door is sealed up and the firing begins. It occupies from 60 to 70 hours. The oven takes the same time to cool, but the ware which is withdrawn from it is quite dull, without any of the familiar shiny appearance. In order to get this glazed surface, the ware is dipped into another special slip, and when it is dry it is again fired. Should it have any decorations, such as gold bands, it has to be fired a third time. Some articles with beautiful colored designs have to be fired as many as a dozen times These are, of course, expensive.

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The of Mary , Street, Wellington Gothic of in Australisia. full description, see Article this publish week. of As a appeal still an devout for contributions is necessary.