105 Dlt. J. STENHOUSE ON PLATlNISED CHAKCOAL VIII.-On Ylutinised Charcoal. By DR.JOHNSTENHOUSE, LLD. F.R.S. THE lighter kinds of wood charcoal owing to the nine volumes of oxygen gas contained in their pores possess a considerable power of oxidising the greater number of easily alterable gases and vapoura. The absorbent power of charcoal however is comparatively much greater than its capacity for inducing chemical combination. In this respect charcoal presents a remarkable contrast to spongy platinum which though inferior as an absorbent for some gaseous substances,- such for instance as ammonia of which spongy platinum absorbs only 30 volumes while charcoal absorbs 90,-is ncvertheless immensely more effective both as an oxidiser and as a promoter of chemical combination generally.As it is desirable for some purposes while retaining the absorbent power of charcoal unimpaired to increase its oxidating influences it struck me that this important object might be easily effected by combining the charcoal with minutely divided platinum. In this way a combination is produced to which I have given the name of platinised cbarcoal which possesses the good pro- perties of both of its constituents. In order to platinise charcoal nothing more is necessary than to boil the charcoal either in coarse powder or in large pieces in a solution of bichloride of platinum and when the charcoal has become thoroughly impregnated with the platinum which seldom requires more than ten minutes or a quarter of an hour to heat it to redness in a close vessel-a capacious plati- num crucible being very well adapted for this purpose.When 150 grains of charcoal were impregnated with nine grains of platinum by the process just described the charcoal was found to have under- gone no change in its external appearance though its properties Bad been very essentially altered. When a few grains of this platinised charcoal were passed up into a mixture of dry oxygen and hydrogen in the proportions to form water over mercury the two gases rapidly combined in the course of a few minutes precisely iu the same way as when a clay ball of spongy platinum is 2myloyed. When how-ever a fragment of charcoal containing a considerably larger propor- tion of platinum was passed up into a sirnilar gaseous mixture the gases instantly combined with explosive violence just as if platinum-black had been used.If pieces of cold platinised charcoal are held in a jet of hydrogen they specdily become incandescent and inflame thc gas. l’latinised charcoal when slightly warnled likewise rapidly lQ6 DR. J. STENHOUSE ON PLATINISED CHARCOAL. becomes incandescent in a current of coal gas but the jet of gas is not inflamed owing to the very high temperature a white heat which is required for this purpose. In the vapour of alcohol or wood-spirit platinised charcoal becomes red hot and continues so till the supply of vapour is exhausted. In the course of a few hours spirits of wine in contact with platinised charcoal and air is converted into vinegar.I find that two per cent of platinum is sufficient to platinise charcoal for most purposes. Charcoal containing this small amount of platinum causes a mixture of oxygen and hydrogen tocombine perfectlyin about a quarter of an hour and this is the strength of platinised charcoal that seems best adapted for charcoal disinfectant respirators. Charcoal containing one per cent. of platinum causes a mixture of oxygen and hydrogen to combine in about two hours ;and charcoal containing the extremely minute quantity of & per cent. platinum produces the same effect in from ti to 8 hours. Ylatinised charcoal seems likely to admit of various useful applications one of the most obvious of these is its excellent adaptability to air-filters and respirators for disinfectant pnr- poses.It is plain that no easily alterable organic vapours such as effluvia or miasmata can remain in contact even for a few minutes with platinised charcoal without being destroyed their carbon being converted into carbonic acid and their hydrogen into water. Platinised charcoal also seems likely to prove a highly useful appli- cation to malignant ulcers and similar sores on which I confidently expect froni its powerful oxidating properties that it will act as a mild but effective caustic. Perhaps however as an application to sores platinised asbestos either alone or in combination with platinised charcoal might be found more manageable. In those diseases also where the internal use of charcoal has been found beneficial I should think that platinised chazcoal may be advantageously substituted. In Bunsen’s carbon battery also the employment of platinised charcoal may I think be advantageously tried. It is clear that the amount of platinum in the charcoal may be varied almost at pleasure according to the strength of the platinum solution employed in its preparation and the purposes to which the charcoal is intended to be applied. Almost any form and even very considerable dimensious may be given to the platinised charcoal,- circumstances which greatly extend the range of its applications.