The Optical Magic Lantern Journal (November 1895)

A point in the construction of what are now turned magnetic watches was clearly shewn upon the screen as illustrated in the | accompanying dia| is | gram, which from the Journal of the Franklin Institute. Two hair-springs are the poles horse-shoe net. One is made of a non-magnetic metal and _ The Optical Magic Lantern Journal and Photographic Enlarger. the | other of magnetic | steel. In the case of the non-mag netic metal, the © shape remains un © altered, but in the : case of the mag netic hair-spring it is drawn towards the attracting pole, and distorted. A simple experiment such as this would be quite indiscernible if seen from the lecture-table, but by means of the lantern | good the phenomena may be clearly seen by all filled with thin wire (a), at the two tubes (m) and (N) which are provided with taps (not present. —— :0:.—_ A Safety Jet of 1832 and 1895. years ago, Hemming introduced about that time what was to be an impossibility for the gases to fire back under the most severe conditions imposed at a 183 | of them, and this was carried to such an extent that it was eventually almost an impossibility | to obtain them made in thoroughly reliable style, so they ultimately fell into disfavour. History, however, often repeats itself, and once again we are likely to have a somewhat similar kind of jet upon the market, for Mr. ; Thomas Goodwin an enthusiastic lanternist of | Rugby has obtained a patent for a jet with a . packed tube. supported below ~ it will be seen that this jet is constructed on of a mag: | In the accompanying drawings principles. The tube (a) is closely shown) the oxygen and hydrogen are respectively admitted, the said supplies being further . controlled by the screw down tap (L); when this THOosE who were active lanternists about sixty | tapis screwed down the plug (x) closes theoxygen will doubtless recollect that Mr. J. , side altogether, but it being provided with a ' small slot (kK 1), sufficient hydrogen is allowed termed asafety mixed jet, in which it was found 0 pass to serve as a bye-pass. passing through (a) is collected at (p), and is The gas after conducted via (rg) to the nipple (r.) The holder meeting of one of thescientific societies of London. Limelight which appeared in our August num ber, he gives a description of this jet which | consisted of a brass cylinder filled with equal | lengths of brass wire, so fine that it took Colouring Lantern Slides.—No. 1. between four and five thousand to fill the cylinder although it was only of one inch in diameter. It had been found out that if a larger diameter of wire were used, there would under certain conditions be a chance of the flame receding through them, consequently in — great exactitude the original one of the inventor. | For a long time they were well-made and | enjoyed great favour, but by degrees certain | makers introduced what they thought improve| ments, which certainly cheapened the making | for the lime which is mounted on (P) is set at an In Mr.W, H. Harrison’sarticleon the Birth ofthe _ angle of seventy degrees from the stuffed portion of the jet tube. ——:o:—— By A. W. 5S. THE art of painting in transparent colours is an attractive one to persons who possess patience and taste in the arrangement of tints. When making them it was necessary to copy with | the outline and shading of a picture have been already done by photographic means, the application of a few washes of colour will frequently enhance the beauty of the picture considerably, although the work may only occupy a few minutes.