A communication by Mr. George W. Walker, of the University of Glasgow, Scotland, he describes a method of reversing static induction machines. He observed accidentally that on stopping a small Voss machine and giving it two turns in the wrong direction, the poles had been reversed. The experiment was repeated a number of times and invariably the reversal occurred. The effect was then tried with a vacuum discharge tube connected to the knobs. While the tube was fresh the reversal occurred but seldom. It was found, however, that if the discharge was made to pass by connecting one terminal of the tube to earth and the other terminal to one pole of the machine, while the second pole was kept insulated, the reversal invariably occurred when the procedure mentioned was followed. Next, a large Wimehurst machine was tested, with the same results. It was noticed, however, that when the induction rods were so arranged that the machine excited both ways, the reversal did not occur. The author believes that this provides a way of getting the discharge to pass in whatever direction is required.

An exhibit at the recent meeting of the Society of German Plumbers which attracted considerable attel. tion, was that showing an invention of Chemist Blau of Augsburg:, for the manufacture of fluid gas from the residuum of petroleum and heavy mineral oils. The inventor says this gas may be manufactured very cheaply where there is an abundance of petroleum, and that it may be transported from one place to another in cylinders as easily as carbonic acid gas. The gas may be used for lighting churches, halls and detached buildings, and in small tanks may be used in lighting automobiles. The Blau gas makes a very brilliant light for street lighting, and is very difficult to explode.

It has been discovered recently that the slime or residuum from the thermal springs at the city of Baden-Baden, Germany, contains very powerful radium. Prof. H. Gertel, of Wolfenbuttel, Germany, says this radium is forty times more powerful than that found in the residuum of cold-water springs or in mud baths. Previously the residuum from the water at Baded Baden was considered worthless by the scientific world and was discarded, but it is now carefully collected and sent to laboratories. For hundreds of years, in fact since the time of the Roman occupancy, persons have claimed that this slime possessed healing qualities, but the matter was regarded by scientists as a superstition. The hot baths at Baden-Baden are very beneficial in the treatment of rheumatism, and are visited annually by thousands suffering from that disease.

Last April a Canadian company installed a plant at Vancouver for the manufactnre of wire wound pipe, since which time between thirty and forty carloads have been shipped to the Northwest Territories, Manitoba and Vancouver Island, and other orders are on hand which will be filled within a very short time. It is claimed that this pipe is superior, for water-supply purposes, to iron pipe and can be furnished at less than half the price. Besides this, it is much lighterto ban-die and is not so liable to burst upon freezing, as pipe made of iron. Large quantities of this pipe are being put into use by mill owners and mining engineers in lieu of flumes, as its use results in the saving of water and repair. This new industry seems to have a good future before it.

An extremly simple method of cutting a gage glass is deseribed in the "American Machinist." It consists of taking a match, cutting it and thoroughly wetting the head. Then, after measuring the glass, put the wet match head inside the glass where it is to he cut and turn the glass several times until a ring is formed on the inside. Now bold a lighted match under this mark and the giass maybe easily separated at the desired point. This method of cutting the glass should be more accurate than using a file to mark and break off the glass.

There are weather prophets and weather prophets, but there is a stone which it is asserted unfailingly foretells changes in the weather. This stone was found in Finland many years ago by an explorer and has been watched by scientists with great interest. It is known as the samakuir, and presents a white mottled appearance in sunshine, gradually turning from gray to black as a rainstorm approaches. The samakuir is made up of clay, nitre and rock salt. In dry weather the salt in the stone is prominent, but when the air is filled with moisture the salt absorbs the moisture and turns black, thus acting as a barometer.

Parchment paper is made by dipping ordinary unsized paper for a few seconds in concentrated sulphuric acid mixed with one half its volume of water and then quickly removing all traces of the acid. The paper thus treated undergoes a remarkable change, it having acquired a parchment like texture, translucent and becomes five times stronger than ordinary paper. Chloride of zinc is also used to impart a parchment effect to paper.