[89] Experience has not confirmed the value of this suggestion. Davy imagined that the vegetable fibre was injured by the saline residuum; and having found that muriate of magnesia was less corrosive than muriate of lime, he was led to propose the substitute above stated. The fact, however, is, that the fibre is injured by the chlorine; and as this body has only a slight affinity for magnesia, it too quickly abandons it; and consequently the oxymuriate of lime is still preferred. It has been very truly observed, that all knowledge which is gained tends towards the acquisition of more, just as the iron dug from the mine facilitates in return the working of the miner. Never was this truth more forcibly illustrated than by the discovery of the nature of chlorine. In the progress of that train of enquiry, which became necessary for the adjustment of our views as they regarded the combinations of that body, Davy discovered a series of new compounds, the history of which he communicated in successive papers to the Royal Society. In a memoir read in February 1811, entitled, "On a Combination of Oxymuriatic Gas and Oxygen Gas," he announced the existence of a _protoxide_ of chlorine, under the name of _Euchlorine_; and in a communication from Rome in the year 1815, he described another compound of chlorine and oxygen, containing a still larger proportion of this latter element, and which has since been made the subject of a series of experiments by Count Stadion of Vienna. As it does not exhibit any acid properties, Dr. Henry proposes to call it a _Peroxide_, in preference to _Deutoxide_; thinking it probable that intermediate compounds, between this and the protoxide already mentioned, may be hereafter discovered. His paper on _euchlorine_ abounds with interest. He found that by acting on the salts formerly denominated _hyper-oxymuriates_, by muriatic acid, the gas evolved differed very greatly in its properties, with the different modes of preparing it. When much acid was employed with a small quantity of the salt, and the gas was collected over water, it was not found to differ from oxymuriatic gas; but when, on the other hand, the gas was procured by means of a weak acid, and a considerable excess of the salt, at a low heat, and was collected over mercury, it possessed properties essentially different. Its colour, under such circumstances, was of a dense tint of brilliant yellow-green, whence the name of _euchlorine_.[90] When in a pure form, this gas is so readily decomposed, that it will sometimes explode during the time of its transfer from one vessel to another, producing both heat and light with an expansion of volume,[91] and it may always be made to explode by a very gentle heat, often even by that of the hand. [90] From [Greek: eu] and [Greek: chlôros].