PHOSPHORUS PASTE. Syn. Anti-arsenical rat-poison, Phosphor-paste. Prep. 1. Phosphorus, 1 oz.; warm water, 1 pint; place them in a bottle, cork it, and agitate them well together, until the phosphorus is reduced to a minute state of division, adding towards the end moist sugar, 1⁄2 lb.; next add of lard (melted by a gentle heat), 1 lb., and repeat the agitation until the whole is nearly cold; when cold, form it into a stiff dough with oatmeal or barley meal, and make this into small balls or cakes; lastly, dry these in the air, without artificial heat.
2. (Simon.) Phosphorus, 8 parts; water (lukewarm), 180 parts; mix in a mortar, and add of rye meal, 180 parts; when cold, further add of butter or lard, 180 parts; sugar, 125 parts; and mix the whole thoroughly together. This is the formula authorised by an ordinance of the Prussian Government, dated April 27th, 1843.
Obs. Rats, mice, &c., eat the above composition with avidity, after which they soon die. It is said that the best method of using it is to place small pieces of it in and about the holes, with some water in a shallow vessel for them to drink. It has the advantage of retaining its efficacy for many years, and is less dangerous to human beings than compositions containing arsenic, whilst it is even more effective for the purpose for which it is employed. Some persons recommend the addition of a little oil of rhodium or oil of aniseed. See Rats, &c.
PHOS′PHURET. Syn. Phosphide; Phosphoretum, Phosphidum, L. A compound of phosphorus with a metal or other basic radical. See the respective Metals, &c.
PHOSPHURETTED HY′DROGEN. Syn. Phosphoretted Hydrogen. See Hydrogen.
PHOSPHATIC DIATHESIS. Syn. White Gravel. A morbid condition of the system, characterised by the deposition in the urine of certain salts of phosphoric acid or phosphates. In this affection the urine, contrary to its
normal condition, is always alkaline, and the nature of the phosphatic deposit is influenced by the source of the alkalinity. If, as most frequently happens, this is owing to the presence of carbonate of ammonia (formed by the decomposition of the urea by the bladder mucus), the deposit will be found to consist of the triple phosphate, or phosphate of magnesia and ammonia, almost always associated with a small quantity of amorphous phosphate of lime. Under these circumstances the urine is pale in colour, and upon standing soon decomposes, in doing which it gives off a strong ammoniacal odour. Phosphatic diathesis is a frequent accompaniment of spinal affections and of chronic inflammation of the mucous lining of the bladder.
In mild attacks the best treatment consists in living rather generously, and in the administration of vegetable tonics combined with proper doses of the mineral acids.
PHOTOG′RAPHY. Syn. Heliography. The art of producing images on prepared surfaces by means of the actinic or chemical rays of the sun’s light. The principal photographic processes now in use are the positive-, negative-, and dry-collodion processes, in each of which a thin film or skin of iodised collodion forms the sensitive surface, a plate of glass being generally used as the foundation of the film. In a positive picture the ‘lights’ are silvery white by reflected light, and the ‘shades’ are produced by a ‘backing’ of black varnish or velvet, showing through the glass plate. In a negative picture the ‘lights’ are of a dirty yellow or brown by reflection, and being formed by opaque deposits, appear dense black by transmitted light. Negatives are used in the various paper-printing processes; they are placed upon prepared paper and exposed to direct light, which darkens those parts of the paper not protected by the opaque ‘lights,’ and thus produces positive prints with natural lights and shades. In this way the portrait ‘cartes de visite’ and other paper photographs are formed.
Of late years there have been devised a great variety of new photographic processes, some of which are given below, together with modern formulæ for the principal solutions, &c., in general request by the photographer.