The London dispensatory, containing: I, the elements of pharmacy; II, the botanical description ... and medicinal properties, of the substnaces of the materia medica; III, the pharmaceutical preparations and compositions of the London, Edinburgh, and Dublin Colleges of Physicians ... a practical synopsis of materia medica, pharmacy, and therapeutics : illustrated with many useful tables and copper-plates of pharmaceutical apparatus / by Anthony Todd Thomson.

  • Thomson, Anthony Todd, 1778-1849.
Date:
1818
Catalogue details

Licence: Public Domain Mark

Credit: The London dispensatory, containing: I, the elements of pharmacy; II, the botanical description ... and medicinal properties, of the substnaces of the materia medica; III, the pharmaceutical preparations and compositions of the London, Edinburgh, and Dublin Colleges of Physicians ... a practical synopsis of materia medica, pharmacy, and therapeutics : illustrated with many useful tables and copper-plates of pharmaceutical apparatus / by Anthony Todd Thomson. Source: Wellcome Collection.

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    Substances burnt, 1 lb.. ' A - 1 Oxygen ‘ consumed in ibs. Ice melted in lbs. Lavoisier. Crawford. 1 Dalton. Hydrogen - - - 6 295 480 320 ] Carburetted hydrogen 4 85 Olefiant gas - - - 3-5 j 88 Carbonic oxide - - 0*68 25 Oil ------ 3*5 148 89 104 1 Wax - - - - - 3 *5 133 97 104 j Tallow - - - - - 3*5 104 I Oil of turpentine - - 60 Alcohol - - - 58 iEther - - - - - 3* i 62 Phosphorus . - - - 1* 5 100 60 Charcoal - - - - 2* 8 96*5 69 40 Sulphur - - 1*36 20 Camphor - - - - 70 Caoutchouc - - - 42 From this table it appears that hydrogen gas would form the best fuel, where a high temperature is required. c. Percussion, as far as it applies to solid bodies, is another source of caloric. Smiths, for instance, are in the habit of kindling their fires by means of an iron rod, which is smartly and quickly hammered until it becomes red-hot; and sparks are produced by the collision of hard bodies, particularly of flint with steel. This effect appears to arise from condensa¬ tion, or forcing the integrant particles of the bodies closer together, so as to dislodge the latent caloric they contain, and give it out in the form of sensible caloric. The specific gravity of iron is increased *052 by being hammered; and it becomes so hard and brittle that it cannot again be heated by per¬ cussion, until it has been exposed for some time to a red heat in the forge. By the collision of flint and steel the oxidize- ment of the steel is also effected, the sparks being small in¬ candescent pieces of oxidized iron. d. Friction is also a source of caloric. It is a well known fact, that a considerable quantity of free caloric is disengaged when two substances are smartly rubbed together; but the real source of the caloric thus evolved, still remains unknown. e. Finally, mixture, or the chemical union of two substances, in many cases evolves caloric. This always takes place when the density or specific gravity of the mixture is greater than the mean of the substances mixed; as in the mixture of alcohol and water, or of sulphuric acid and water; and much caloric is also evolved when water is thrown upon quicklime, owing