314 Cambridge Philosophical Society. 



absorb about five gallons, and is then removed -, and after drying in 

 the air it is fit for use. ' 



Timber thus prepared has stood extraordinary trials against parts 

 of the same timber unprepared, having been introduced for several 

 years into situations liable to rot, and resisted, whilst the other ran 

 to decay. 



Mr. Faraday having full trust in the preservative powers, had more 

 particularly examined the state of the corrosive sublimate with re- 

 ference both to its removal by washing or soaking, and so leaving the 

 timber liable to decay after, and to its volatility, and the consequent 

 production of a bad atmosphere, for he had found corrosive sublimate 

 to be volatile at common temperatures. 



Portions of canvass and calico, which had been prepared by Mr. Kyan, 

 were therefore washed several times, until water could remove nothing 

 more ; but on digesting them in dilute nitric acid, mercury was found, 

 proving that the substance had been previously in combination. Again, 

 such washed portions, together with similar specimens unprepared, 

 were put into a cellar to decay, and in eight weeks had undergone no 

 change ; whilst the others were covered with mould, mildew, &c. ; — 

 so that the preservative powers remain. Being in this state of com- 

 bination capable of resisting the action of water, Mr. Faraday ex- 

 pressed himself free from any fear as to injurious effects arising from 

 the volatility of the substance. 



March 1. — Mr. Faraday ; An Investigation of the Velocity and Na- 

 ture of the Electric Spark and Electric Light. This investigation, 

 though delivered by Mr. Faraday, has been carried on by Mr. Wheat- 

 stone. We refrain from entering into it here, as we expect to have 

 the pleasure of submitting the whole to our readers. 



March 8. — Mr. Wheatstone on some Properties of the Impressions 

 produced by Light on the Organs of Sense. This also, we hope, will 

 appear shortly in our pages. 



March 15 — Mr. Donaldson on the Drainage and Sewerage of Lon- 

 don, with Mr. Martin's Plan for its Improvement. 



March 22. — Mr. Carpmeal on Recent Improvements in the Salt 

 Works of Great Britain. 



CAMBRIDGE PHILOSOPHICAL SOCIETY. 



Feb. 25. — The Rev. W. Whewell read a continuation of his Me- 

 moranda on the Architecture of Normandy. 



After the meeting, Professor Airy gave an account (illustrated by 

 models and diagrams) of his researches into the numerical value of 

 the mass of Jupiter. He observed that, next to the elements of the 

 planetary orbits, this value is the most important for the calculation 

 of the phenomena of the solar system, on account of the magnitude 

 of the perturbations which it produces. Its effects on the motion of 

 Saturn are very considerable; those on the small planets still greater; 

 and those on Encke's comet so great, that a few years ago the truth 

 or falsehood of the theory of resistance depended upon the use of 

 one or other of two values of the mass differing only one eightieth 

 part. He then gave an historical account of the principal determi- 



