FOR GENERAL READERS. 



Vol. I.] 



April, i? 



[No. 2. 



CONTENTS. 



Current Events 25 



General Notes 28 



The Fish Torpedo (illits.) 31 



Notes on Heating Buildings (illiis.) . . 33 



A New Industry in Skye 37 



Technical Journalism Fifty Years 



Ago {I/his.) 37 



Notes on Colour 40 



Earthquakes and their Causes 41 



The Patent Office 43 



Reviews of Books : — 



Practical Electricity, by Professor 



Ayrton 44 



First Year of Knowledge, by Paul 



Bert 45 



Railway Problems, by J, S. Jeans 1. . 45 

 Papers read before Societies. 

 The Royal Institution : — 



Professor Max Muller on the 

 Science of Thought 45 



PAGE 



Captain Abney on Sunlight 



Colours 46 



The Institution of Civil Engineers : — 



Col. Maitland on Gun Steel 46 



The Geological Society 45 



The London Sanitary Protection 



Association 45 



Record of Scientific and Technical 



Societies 47 



Applications for Patents 48 



CURRENT EVENTS. 



City and Guilds of London Institute. — A well-attended 

 and very interesting conversazione was given by the 

 Council of the City and Guilds of London Institute in the 

 New Central Institution at South Kensington, on the evening 

 of i6th March. The building is large, and apparently well 

 arranged for accommodating students in the many branches 

 of technical education which are taught. The thoroughly 

 practical as well as scientific nature of the instruction given, 

 was shown by the machines and apparatus used in the 

 various laboratories and workshops. Prof Unwin, F.R.S., 

 explained the use of the 100- ton testing machine in the 

 Engineering Laboratory, giving a practical illustration by 

 breaking some bars of iron. 



Prof Ayrton also gave a short but very interesting 

 demonstration to a crowded audience in the Physics 

 Lecture Theatre, referring chiefly to Faraday's discovery of 

 the principles on which the modern dynamo machine de- 

 pends. By permission of the Royal Institution he was able 

 to show some of the identical apparatus made with Faraday's 

 own hands, and used by him fifty years ago. For instance, 

 there was his first induction coil made with two pieces of 

 covered wire wound round an ordinary curtain ring; and 

 with this simple contrivance it was proved that after 

 passing a current through one wire there was a second and 

 independent current set up in the other wire as soon as the 

 current passing through the first was stopped. 



Professor Ayrton also showed his audience Faraday's 

 development of this induction coil, by means of which 

 the latter succeeded for the first time in obtaining an electric 

 spark by the transference of mechanical work into electrical 

 energy. This, in fact, was the forerunner of all the dynamo 

 electric machines now used throughout the world, not only 



for electric-lighting but for electric-motors. He concluded 

 by showing in operation several applications of electricity 

 to modern uses. Demonstrations were also given by Mr. 

 J. Sawyer on the Autotype Process ; by Prof Armstrong, 

 F.R.S., on the Production of Madder Colours and Indigo 

 from Coal ; and by Prof Austen-Roberts, F.R.S., on Methods 

 used by the Japanese in Art Metal Work. On a future 

 occasion we hope to give some particulars of this very pro- 

 mising institution. 



Foul Air in Public Assemblies.- -The waste of life that 

 is due to breathing foul air is a quantity beyond the possi- 

 bility of gauging, or even estimating ; but, at any rate, it 

 must be very great amongst people leading sedantry lives. 

 It is a matter for congratulation, therefore, that some reliable 

 tests are about to be made in this country on the subject. 

 Dr. Russell, of Edinburgh, a member of the Public Health 

 Committee, has taken the matter in hand, and has already 

 made some tests. The first examinations were made at the 

 beginning of last month, in the rooms of the Edinburgh 

 Council Chamber. These, we understand, are to be the first 

 of an extensive series of tests in which the air in schools, 

 halls, theatres, and some of the churches in the northern 

 capital, will be made the subject of examination. The 

 investigations will be made by Dr. Hunter Stewart, who is 

 the director, under Sir Douglas Maclagan, of the Public 

 Health Laboratory, in the Edinburgh University. He will 

 have associated with him Mr. Cosmo Burton, B.Sc, who 

 will act as analyst during the tests. 



The apparatus employed in making these tests will con- 

 sist of three different sets. One will be used for testing 

 for carbonic acid gas, a second for germs, and a third for 

 organic matter. The following description of this appara- 

 tus is taken from a northern contemporary : — 



