A treatise on chemistry. Vol. 1, The non-metallic elements / by Sir H.E. Roscoe & C. Schorlemmer ...
- Henry Enfield Roscoe
- Date:
- 1881
Licence: Public Domain Mark
Credit: A treatise on chemistry. Vol. 1, The non-metallic elements / by Sir H.E. Roscoe & C. Schorlemmer ... Source: Wellcome Collection.
Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.
28/792 page 12
![cipitate to be made witliout any additament, will, perchance, scarce be able to give a more likely account of the consistency and degree of fixity, that is obtained in the mercury; in which, since no body is added to it, there ai)pears not to be wrought any but a mechanical change, and though I confess I have not been without suspicions that in philosopliical strict- ness this precipitate may not be made per sc, but that some penetrating igneous particles, especially saline, may have asso- ciated themselves with the mercurial corpuscles. We owe the next advances in chemistry to the remarkable views and experiments of Hooke {Mici-ograpliia, 1665), and of Ms successor John Mayow {Ojoera Omnia Ilcdico-jjhysica, 1681). The former announced a theory of combustion, which althougli it has attracted but little notice, more nearly approached the true explanation than many of the subsequent attempts. He pointed out the similarity of the actions produced by air and by nitre or saltpetre, and he concluded that combu.stion is effected by that constituent of the air which is fixed or combined in the nitre. Hooke did not complete his theory or give the detail of his experiments, but this work was undertaken by Mayow, who in 1669 published a paper, Dc Sale Nitro d Spiritu Nitro-aereo, in which he points out that combustion is carried on by means of this spiritus nitro-aereus (another, and not an iuajDi^ropriate name for what we now call oxygen), and he also distinctly states tha,t when metals are calcined, the increase of weight observed is due to the combination of the metal with this spiritus. ]\Iayow was one of the first to describe experiments made with gases collected over water, in which he showed that air is diminished in bulk by combustion, and that the respiration of animals pro- duces the same effect. He proved that it is the nitre-air which is absorbed in both these processes, and that an inactive gas remains, and lie drew the conclusion that respiration and com- bustion are strictly analogous phenomena. Tliere, therefore, is no doubt that Mayow clearly demonstrated tlie heterogeneous nature of air, although his conclusions were not admitted by his co- teliipoi'aries. Another theory which was destined greatly io influence and benefit chemical discovery, was advanced about this time by J. J. Becher (IBl'o—.1681), and subsequently much developed and altered by G. E. Stahl (1660—1734). It made special reference to the alterability of bodies by fire, and to the explanation of the facts of combustion. Becher assumed that](https://iiif.wellcomecollection.org/image/b21449016_0028.jp2/full/800%2C/0/default.jpg)
