HISrORT of the SOCIETY 



17 



Phy/. CI. Dr Monro read a paper, concerning the Commu- 

 catlon of the Ventricles of the Brain with one another, in 

 Man and Quadrupeds. This paper is pubhfhed in Dr Monro's 



nication of the Ventricles of the Brain with one another, in Dr won'ro on 



the comp'unica- 

 tion of the ven- 



book, entitled, Three Treatifes, &c. brain. 



Mr Keith alfo communicated an Improvement of the Mer- 

 curial Level, defcribed in the Second Volume of the Tranfadlions 

 of the Society. 



This improvement conlifts in a contrivance for avoiding the 

 trouble of pouring the mercury out and into the level, every 

 time it is ufed. Befide the canal of communication at the bot- 

 tom, between the two upright columns of mercury, on which 

 the Jlots fwim, (fee Vol. II. Part II. No. III.), there is, in the 

 new conflrudlion of the inftrument, another canal, parallel to 

 the former, cut in the vipper part of the wood, which allows 

 the air to circulate freely, according as the mercury below rifes 

 or falls. The whole is made perfed:ly clofe, fo that no air can 

 get admittance. 



The inftrument 'may be carried about in this manner, with 

 the mercury remaining in it ; and though by agitation that 

 fluid calcines, and is converted into a grey powder, this only 

 happens when it has free accefs to vital air ; and as all fuch ac- 

 cefs is here prevented, the mercury will not lofe its metallic 

 luftre. \ 



The level, in this form of it, as it requires no previous ad- 

 juftment, is very commodious, and, when much accuracy is not 

 required,^ may be ufed with advantage. 



Phj/, CI. Dr Anderson read a paper, entitled, Obfervations 

 on Wool-bearing Animals, 



Pbyf. CL Mr Play fair communicated an Abftrac^ of a 



Journal of the Weather, kept at his Houfe in Windmill Street, 



Vol. IV. c for 



Mr Keith on an 

 improvcruent of 

 the mercurial 

 lerel. 



1795' 

 Jan. 5. 



Dr Anderfon 

 on wool-bear- 

 ing animals. 



Feb. 2. 



Mr Play fair on. 

 the weather of 

 1794. 



