In the casting of brass the pattern should be slightly larger to insure the proper dimensions. The shrinkage allowance on patterns for casting brass is 3-16 inch to the foot in length or diameter of the pattern.
Development of the internal combustion engine for marine purpose means that, in the adoption of the now familiar motor boat, the same ranges of power and action as are obtained by the best reciprocating engines and boilers can be secured at one-sixth of the weight with the new motor. The British Admiralty are so convinced of the advantages of the combustion engine that they have carried out at sea a series of experiments, and there is some talk of utilizing this type of engine in the new torpedo boats which are about to be built.
To doubt and be astonished is to recognize our ignorance, and this is the first step toward acquiring knowledge. - Lord Chesterfield.
A curious fact has recently been brought to light, namely, that a man's mind is so constituted that it cannot work normally in a circular room. The discovery was made in connection with Minot Ledge light-house, which is a piece of engineering of the highest order. The tower being circular, space is in great demand and, accordingly, everything is made to conform to the shape. The beds are circular, the tables and benches are half-moons. There have been five well marked cases of insanity in the men who have worked here, and a number of others have been removed before their minds become entirely unbalanced. On being placed in rooms having the ordinary number of angles and corners, the sufferers rapidly improved and the theory has been propounded that the shape of the lighthouse rooms is responsible for the trouble. Experts in mental diseases have made a study of the conditions existing at Minot Ledge, and they say that there is no point on which the eye may rest, so that it travels around and around until the result becomes maddening.
Radium acts upon the chemical constituents of glass porcelain and paper, imparting to them a violet tinge, changes white phosphorus to yellow, oxygen to ozone, affects photograph plates and produces many other curious chemical changes.
Emery paper and cloth are made by dusting finely ground emery upon paper or cloth coated with thin glue.
The official organ of the ministry of commerce and trade in Prussia publishes the following statistics of the trade and technical schools in Prussia at the beginning of 1905: Giving instruction in machine building and other productions of the metal working industries, 19 schools attended by3055 scholars; architecture and the building trades, 32 schools attended by 5039 scholars; art trades and various high-class crafts, 26 schools and academies attended by 3061 students. Five of the last named schools were State institutions and the other 21 received subventions from the government. These schools had evening and Sunday classes, which were attended by 12,252 students in addition to the number of full course day scholars given. The textile trade schools instructed 1608 males and females, and 237 in the weaving workrooms. There were 1290 technical and 290 commercial finishing schools, with 201,716 and 3t,670 scholars respectively, and 428 technical schools, organized and supported by industrial associations or craft guilds, having 28,043 scholars. The State grants subventions to 1237 of the finishing schools.
What is called a heat-proof putty is made by mixing burnt lime with linseed oil and boiling down to the usual consistency of putty and allowing the plastic mass to spread out in a thin layer to dry in a place where it is not reached by the sun. It can be warmed over a lamp or otherwise for use, and on cooling is hard again.