2(58 The Progress of Physical Discovery. [MARCH, 



meter for water, invented by Count Rumford, made repeated experi- 

 ments, which, though they did not succeed in shewing what does 

 produce animal heat, proved that it must be referred to some other cause 

 than the fixation of oxygen. The clearing away of false notions in 

 physics, as in all other things, is necessarily a preparatory step to the 

 ascertainment of truth. 



Dr. Liebig, in 1823, occupied himself with those combinations of 

 silver or mercury with alcohol or nitric acid, which are known to ful- 

 minate so powerfully. This young German chemist precipitated the 

 fulminating principle in the form of a white powder, which is one of the 

 most complicated compositions that have yet been found, presenting a 

 metallic substance, with the ordinary elements of animal matter, viz., 

 oxygen, hydrogen, and azote. Professor Doeberimer . of Jena, in this 

 year also, made a curious discovery of the property of Platina, when 

 passed through a mixture of oxygen and hydrogen, to. effect the com- 

 bination of these two gases, and to produce a heat by which it becomes 

 itself red-hot. M. Chevreul, continuing his researches into the theory 

 of saporification, discovered two principal acids in butter, the butiric and 

 capric ; one in the fat of the dolphin, named phocenic ; and another in 

 the fat of mutton, called hircic. M. Payen also found, in the bulbs of 

 the Dahlia, a new substance, called Dahline, analogous in some respects 

 to starch and gelatine, and which is converted, by sulphuric acid, into 

 incrystallizable sugar. 



Mr~ Dalton, during the last seventeen years, had been making experi- 

 ments on the mountains in the north of England, to determine the quan- 

 tity of dew contained in water in a spring situated in an elevated place, 

 and the degree of temperature of this water. In 1824 he ascertained the 

 following results : that the quantity and density of vapour diminish as 

 you rise ; that, whenever there is a thick fog, the temperature of the 

 atmosphere, and the degree to which dew is produced, are the same ; 

 that, when a mountain is enveloped in clouds, we find, in rising, very 

 little variation between the atmospheric temperature and the point where 

 the dew begins to form ; and that the atmospheric temperature generally 

 sinks one degree of Fahrenheit to 240 feet of perpendicular elevation 

 when the heat of the day has reached its maximum ; and under the same 

 circumstances, that where the clew is formed, diminishes by one degree 

 to every 390 feet. As the dew-point and the atmospheric temperature 

 approach each other as we ascend, we arrive at a certain height where 

 they are the same ; and hence it happens, that the highest regions of the 

 atmosphere are often cloudy, and that the moss on the top of high moun- 

 tains is generally damp. 



It had been some time known that the nature of bodies may be 

 changed by dilatation, but not until this year that compression has the 

 same effect. M: Legmuth verified this proposition by experiments on 

 sulphur, which, by compression, became grey, and detached itself by 

 small parcels, the separation of each of which occasioned a detonation 

 Kke that of the electric spark. The fact of the penetrability of glass by 

 water was this year ascertained, by sinking two hermetically sealed bot* 

 ties 1200 feet in the sea, which, on being drawn up> were found to be 

 filled with water by the powerful pressure of the surrounding liquid. 



M. Savart having made a series of experiments on the vibrations of 

 solid bodies, brought to light the following results of high importance 

 with reference to the theory of molecular attraction : Wherever an in- 



