Boyal Society, 387 



which attempt to account for the phaenomena of the living body, either 

 in health or disease, by an exclusive reference either to the solids or 

 to the fluids which enter into its composition ; or to the influence of 

 an abstract and unknown principle of life ; or to that of physical or 

 chemical agents ; or to the functions of the nervous, or of the vas- 

 cular systems. For the establishment of the sciences of physiology 

 and pathology upon the most solid foundations, the author is of opi- 

 nion that all the circumstances above mentioned sliould be duly taken 

 into account, and allowed their respective and proportionate degree 

 of influence. 



10. "On the Water Barometer erected in the Hall of the Royal 

 Society," by J. F. Daniell, Esq. F.R.S. Professor of Chemistry in 

 King's College, London. 



The author having long considered that a good series of observa- 

 tions with a water barometer would be of great value as throwing 

 light upon the theory of atmospheric tides, of the horary and other 

 periodic oscillations of the barometer, and of the tension of vapour at 

 different temperatures, was desirous of learning whether any such 

 series of observations had ever been made. But he could meet with 

 none having any pretensions to accuracy ; for neither those of Otto 

 Guericke, in whose hands the water barometer was merely a philo- 

 sophical toy, nor the cursory notices of the experiments of Mariotte 

 upon this subject contained in the History of the French Academy of 

 Sciences, can be considered as having any such claim. The difficul- 

 ties which opposed the construction of a perfect instrument of this 

 kind long appeared to be insurmountable ; but the author at length 

 proposed a plan for this purpose, which, having been approved of by 

 the late Meteorological Committee of the Royal Society, was ordered 

 by the President and Council to be carried into execution. 



The author then enters fully into the details of the methods he em- 

 ployed for constructing the whole of the apparatus, and for placing 

 it in its present situation in the centre of the winding staircase con- 

 ducting to the apartments of the Royal Society. The tube was very 

 skilfully made by Messrs. Pellatt and Co. at the Falcon Glass-house. 

 It was 40 feet long, and one inch in diameter at its lower end; and 

 so nearly cylindrical, throughout its whole extent, as to diminish only 

 by two tenths of an inch at its upper end. A second tube of the 

 same dimensions was also made as a provision in reserve against any 

 accident happening to the first. ^These tubes were both securely 

 lodged in a square case by means of proper supports. A small ther- 

 mometer with a platina scale, was introduced into the upper end of 

 the tube. An external collar of glass was united to that end by heat- 

 ing it. This was done with a view of giving it additional support, 

 and of preventing it from slipping. This end of the tube was then 

 drawn out into a fine tube ready for sealing with the blowpipe; and 

 a small stopcock was fitted on to it. The cistern of the barometer 

 was forme(l by a small copper steam boiler, 18 inches long, 1 I wide, 

 and 10 deep, capable of being closed by a cock, and having at the 

 bottom a small receptacle for holding the lower end of the tube, so 



