Miscellanies. 381 



tated by carbonate of ammonia ; several of the acids dissolve it 

 without combination, for example, hydrochloric and acetic acids — 

 others change its nature, especially sulphuric and nitric. 



The composition of meconine, deduced from four analyses, is 



Atoms. By calculation. Weight of Atom. 



5. Effects of the thermo-multiplicator . — This instrument was in- 

 vented by M. NoBiLi, (vide Am. Jour., Vol. xxii. p. 370,) and con- 

 sists of a thermo-electric pile, united to a galvanometer. M. Maced. 

 Melloni has rendered it more sensible and more applicable to radi- 

 ant heat by several improvements suggested by the inventor himself. 

 In a letter to Mr. P. Pkevost, M. Melloni enumerates some interest- 

 ing effects exhibited by this instrument. 



Calorific rays proceeding from iron heated to a dull or to a cherry 

 red, are completely stopped by a stratum of water of two or three 

 millimetres in thickness. It is the same with heat from the flame of 

 alcohol or sulphur. When the heat of the iron surpasses the above, 

 some rays begin to pass through, and the quantity increases to white 

 heat, conformably to the law which Laroghe found for glass. The 

 quantity of heat transmitted varies also when issuing from the flames 

 of oil, tallow, wax, wood, resin. The greatest effect seems to be 

 produced by an argand lamp, and by the solar rays. 



A singular result is the following, which clearly proves the exist- 

 ence of two very distinct qualities in calorific rays. A thermometer 

 is placed on the front surface of a layer of water, and a thermo-mul- 

 tiplicator, behind the same layer. An iron ball at a dull red heat is 

 brought near — the thermometer rises from 60 to 90°, and the ther- 

 mo-multiplicator remains unmoved. A. double argand lamp is then 

 placed at the distance of a few feet : the thermometer does not move 

 while the thermo-muliiplicaior shows a deviation of 36°. 



The rays from the former source, although endowed wuh great 

 energy, are wanting in that quality which those from the latter source 

 possess — the property of passing through water. 



A slight degree of transparency seems necessary to render a body 

 permeable to radiant caloric, and yet the calorific permeability of dif- 

 ferent media is far from being proportional to their transparency. 



