CONTENTS. IX 



Page 

 Professor J. Clerk Maxwell on the Protection of Buildings from Liglituiug 43 



Sir W. Thomson on Compass Correction in Iron Ships 45 



on Eflects of Stress on the Magnetization of Iron 45 



on Contact Electricity 45 



ACOTTSTICS. 



Mr. R. H. M. BosANQUET on the Conditions of the Transformation of Pendu- 

 lum-Vibrations ; with an experimental illustration 45 



Mr. Colin Brown on true Intonation, illustrated by the Voice-Harmonium 

 with Natural Finger-board 46 



Sir W. Thomson on a Practical Method of Tuning a Major Third 48 



Insteuments, &c. 

 Professor Barrett on a Form of Gasholder giving a uniform Flow of Gas . . 48 



on the new Lecture-Table for Physical Demonstration in 



the Royal College of Science for Ireland 48 



on two new Forms of Apparatus for the Experimental 



Illustration of the Expansion of Solids by Heat 48 



Mr. C. H. GiMiNGHAM on a Modification of the Sprengel Pump, and a new 



Form of Vacuum-Tap 49 



Professor Hennessy on new Standards of Measure and Weight 49 



Mr. G. J. Symons on a new Form of Thei-mometer for observing Earth Tem- 

 perature 49 



on an Unmistakable True North Compass 49 



Sir W. Thomson on a new Form of Astronomical Clock with Free Pendulum 



and Independently Governed Uniform Motion for Escapement-wheel .... 49 

 Mr. W. H. Walenn on Mr. Sabine's Method of Measuring small Intervals of 

 Time 52 



Captain A. W. Baird on Tidal Operations in the Gulf of Cutch by the Great 



Trigonometrical Survey of India 52 



Sir W. Thomson on the Physical Explanation of the Mackerel Sky 54 



on Navigational Deep-sea Sovmdings in a Ship moving at 



High Speed 54 



CHEMISTRY. 



Address by Mr. William Henry Perkin, F.R.S., President of the Section . 65 



Mr. F. H. T. Allan on a Safe and Rapid Evaporating-pan 61 



Mr. J. Banks on Sewage Purification and Utilization 62 



Mr. H. W. Biggs on a new Voltaic Battery 62 



Professor Crum Brown on the Action of Pentachloride of Phosphorus on 



Turpentine 62 



Mr. James T. Brown on Anthracene-testing 62 



Mr. J. y. Buchanan on some Instruments used in the ' Challenger ' 63 



Dr. Cameron on Ammonic Seleniocyanide 63 



Mr. J. J. Coleman on a Gas-condensing Machine for the Liquefaction of 



Gases by combined cold and pressure, recently employed in the manufacture 



of Volatile Liquid Hydrocarbons 63 



on the Chemical Treatment of Town Excretion 63 



Professor Dewah on the Transformation of Chinoline into Aniline 63 



Mr. W. DiTTMAR on the Proximate Analysis of Coal-Gas.— Remarks on 



Reboul's Paper on Pyro-Tartaric Acid 63 



