Show arad wl j perpetual act v ty of rad urn the radium electroscope is a little instrument in which the departure of negative ions from a speck of radium in a sealed vacuum tube per petua lly changes the leaves ol 01 an electroscope also inside the sealed tube while the action Is probably not perpetual so long as the radium lasts say 30 years the tiny leaves of the electroscope will it Is said go on opening and shutting so many times a minute like a clock or a per letual motor there is also an ar ran gement by which the periodical discharges of the electroscope when the leaves touch he side oi the sealed glass tube in which a wire connects two inner coatings of zinc foil 0 earth ring a bell or print a record of every contact of the leaves each dis charge from the outside terminal of zinc foil and wire when th leaf strikes the inner foil is sufficient to act on a similar to thai wa ch is used in wireless telegraphy the as in a wireless telegraphic system is put in a bell circuit and pach time it is acted on by a train of waves it rings a bell with a three milligramme milli gramme speck of radium the bell was rung every seventy sec ands thus a perpetual minute bell could ie devised novelty in envelopes in no other business is there suan a continual search for novelties as in the printer s art the up to date printer a always on tho lookout for something mcw and especially is this true OIL what are generally called nov cities to be successful he must be able to present something that 13 attractive and artistic and at the same time substantial and it Is sel dom that he does two pieces of work alike his work really covers such a wide range that he must be able to present something different tor every business all printers do more or less pam ahlet work and a very unique novelty in this line is that shown in the allus it consists ot an ordinary booklet of any number of pages with the envelope combined therewith the cover Is made larger than the outside bookie allowing an edge of about an inch all around which is artly separated from the main ion by perforation this edge con ains an adhesive substance which an be easily moistened and the back ind front of the cover brought together this eventually seals the en delope and when received can be quickly opened by tearing off the per orated edge the name and address the recipient can be written on he front the same as in the ordinary envelope nv elope and a stamp affixed P cang coal by machine england is soon to have a complete oal screenings plant for the express purpose of picking coals the coal is carried on a traveling belt while standing on each side at short distances pick out the stone shale and other substances as the oal passes along the plant will we picking belts jigging screens evolving tipples and various convey rs together with the necessary steel structural work and gearing the re holving tippler with a diameter of six beet six inches Is arranged to convey ill the coal from the tubs to the screens without waste and to reduce the breakage to a minimum the jig ger sorts into three classes of coal smudge nut and best on the under side of the j aging screen are two steel plate shoots for delivering the nut and slack to the picking belts there are three belts arranged to con vey the coal to the trucks with low ering shoots at the end at the end of each conveyor are three steel plate shoots for delivering the material into the wagons the plant Is designed to deal with an output of tons a day making steel without pig iron reports come from victoria aus aralia ot the successful experiments by the iron steel and metals manu fracturing fac turing company of that city in pro wrought iron and steel without the use of pig iron the magnetic iron sand of new zealand Is treated first with electromagnetic separators so as to leave a pure magnetic iron oxide these particles of ore are dropped automatically into a revolving cylinder in a furnace which uses fuel oil and the waste gases the particles are reduced thus to the metallic form while retaining their in dividu allty from the revolving cyl inders the ore particles drop into a smelting bath working under compressed air the physiological effects of corn pressed air may be interred from the following suggestions men required to work under compressed air should be sound small temperate and at last 25 years old for a pressure of two atmospheres the shift should not exceed tour hours and the time of passage through the lock on coming out should be thirty minutes while for a pressure of five atmospheres the length of the shift should be reduced to one hour and the time in the lock should be twice that amount after leaving the lock on coming away from their work the men should hav a complete rest of one hour a valuable discovery Is a new and peculiar alloy formed of nickel and steel which withstands heat without expansion when made in a certain way it con tracts slightly on being heated since all instruments of precision sut fer errors from changes in tempera ture this quality will greatly benefit measuring apparatus particularly timepieces astronomers will regard with enthusiasm a pendulum certain to stay of constant length regardless of thermal influences surveying ap Is another article that will profit by j |