SCIENCE NOTES.

Digger (Invercargill RSA), Issue 35, 12 November 1920, Page 15

SCIENCE NOTES.

OBSERVATION OF SUNSPOTS. The frequency of sunspots large enough to be A'isible to. the naked eye is greater than is generally supposed. At a recent meeting of the British Astronomical Association it was stated that members of the Solar Section of the society liad observed the sun with tlie naked eye on o02 days during 1919, and on 126 of these days spots had been seen with ihe naked eye. USES OF GLYOERINE. The diversified uses to which glycerine is put indicate its importance in commerce. Most of the distilled glycerine fmds it-s way into the manufacture of explosives, such as nitroglycerine, dynamite, and the more recently develoy,ed high explosives. These are generally a combination of nitroglycerine with gun. cotton or nitrocellulose, and the resulting product is known by a great variety of names. Co,mmerciaIIy pure glycerme is a well known reagent in pharmacy and medicine, where nitroglycerine ltself is sometimes employed. Glycerine enters into a number of technical processes, such | as the manufacture of soaps, inks, waterproof paper, and for tho production of such plastic masses as printing rollers and other masses used in the art of reproduction. Glycerine is also used in'gas meters and tubes which must withstand great cold, and for filHng hydraulic jacks. It is one of tlie Ymportant items in sizing textilas and in that treatment of wine, beer, and vrnegar known as "scheelizing." SOAP FROM CLAY. Soap from clay is the promise made by a group of British chemists wno have been working on the utilisation oi this plentiful material for a number of years. Stripped of all technical verbiage what this group has discovered is a method of making use of China clay which is found in large quantities both in Britam and the United States, not as an adulterant, but as an ingredient in soap-making. Soap, as most people know, is made now from fat, and fat is becoming scarcer and more expensive everv year. China clay is plentiful and cheap. It can be had for the digging and tb,e process of turning it into soap-making material is cheap and easy. It is claimed that it can bo used j up to 50 per cent. in combination with the usuaT fatty a-cids in soap-making, and that, the soap thus made lathers ag well, is as cleansing and as pleasant to use as soap made in the old way of ail fat. The process by which the clay is prepared is simplicity itself. After mining it is purified by a combined washing and chemcal process anci the resultant finely divided clay after being run into a settling tank is dried and is ready for use. It is a soft soapy substance withouta- trace of grit. A NEW ICE CREAM FREEZER. Hitherto the containers for freezing the cream have been somewhat cumbersome, and often not of the best form for easy cleaning. These drawbacks are elimmated in the apparatus known as the "Auto Vacumn Freezer," which consistg of a double cylinder of tinned steel with an air space between the two parts. The ice cream container projects downwards through the top of the inner cylinder, leaving a second space, which, when the apparatus is in operation, is filled with a mixture of salt and ice. The container is fitted with a lid having a cross-bar, the ends of which engage under catches and lock it tightly in position. This inner vessel has a rounded bottom, so that 110 scraps of cream are left in coraers from which they can he scraped out only with difficulty. Such a shape also lends it-self

to easy cleansing. At the bottom of the inner cylinder is an opening with a movable door similar to the lid already desscribed, but provided also with a joint ring to make it watertight. When the freezer is to be used it is turned upsidedown and a supply of ice and salt is put in between tlie inner cylinder and the container. After the movable door has been put in place and tightened under the catches, the freezer is reversed, the cream is put into the container, tho lid fastened down, and in Half-an-hour ihe ice cream is ready without any further effort.