PAINTING. 



563 



and brickwork : we believe that it is 

 composed of burnt oyster-shells, ground 

 glass, scoria from the lead works, and a 

 little colouring matter, according to the 

 shade desired. These, when very finely 

 pounded and sifted, may be kept for 

 years in a dry state, and when to be 

 used, they are mixed with raw linseed 

 oil in the usual manner ; but the mixture 

 should stand a day or two before being 

 laid on. This is an excellent paint for 

 the inside of watering-pots, preventing 

 rust, and tending to their durability. 

 Some waters contain mineral matters in 

 solution, which, if not counteracted by 

 paint, eat the iron into innumerable 

 holes, as also the lead lining of cisterns. 



31. Zend's anti-corrosion paint. — Eighty 

 parts of finely pounded and sifted brick- 

 dust, mixed with twenty parts of litharge, 

 ground together upon a slab with lin- 

 seed oil to a thick paste, and diluted 

 with oil of turpentine, make a paint 

 which has been found to resist oxidation 

 in iron, both when exposed to the weather 

 and the sea. Before proceeding to use 

 this paint, the iron, even if new, should 

 be rubbed quite clear. Indeed, this 

 latter precaution should be attended to 

 in all cases where iron is painted ; 

 for, if neglected, the process of rusting 

 will go on under the paint somewhat as 

 the rot in wood does, if not properly 

 seasoned and dry before the usual paints 

 are laid on. 



Black paint. — The sombre appearance 

 of this colour in general does, and always 

 should, exclude it from gardens and gar- 

 den scenery. For this reason, as well as 

 for those shown below, coal-tar ought 

 never to be employed. There is a decay- 

 ing property in black, depending on 

 colour alone, which has been described in 

 " The Transactions of the Society of Arts," 

 and in " The Civil Engineer," as well as 

 in other periodicals. The writer says — 

 " I have heard many men of considerable 

 experience say, that black is good for no- 

 thing on wood, as it possesses no body to 

 exclude the weather. This is indeed 

 partly the case ; but a far greater evil 

 than this attends the use of black paint, 

 which ought entirely to exclude its use 

 on any work out of doors — viz., its pro- 

 perty of absorbing heat. A black unpo- 

 lished surface is the greatest absorber and 

 radiator of heat known, while a white 



surface, on the other hand, is a bad 

 absorber and radiator of the same ; — con- 

 sequently black paint is more pernicious 

 to the wood than white. Wood having 

 a black surface will imbibe considerably 

 more heat in the same temperature 

 than if that surface were white ; from 

 which circumstance we may easily con- 

 clude that the pores of wood of any 

 nature will have a tendency to expand 

 and rend in all directions, when exposed 

 under such circumstances : the water, 

 being admitted, causes a gradual and pro- 

 gressive decay, which must be impercep- 

 tibly increasing from every change of 

 weather." In following up his argument 

 as to the absurdity of painting ships black, 

 he says—" I am fully persuaded that a 

 piece of wood painted white will be pre- 

 served from perishing as long again, if 

 exposed to the weather, as a similar piece 

 painted black, especially in a tropical 

 climate." The extent of the heat-absorb- 

 ing properties of a black colour have been 

 variously estimated by chemists. So far 

 as paint is concerned, we think its want 

 of popularity depends more on its appear- 

 ance and want of body than on its direct 

 absorbent power. The best black paint 

 is oxide of manganese. Lamp-black and 

 oil, so frequently used, has little body in 

 it, and consequently does not last long. 

 For hinges of gates, and iron-work em- 

 ployed to brace up timber- work, when 

 colour is an object of contrast, it may be 

 used as a finishing coat over three coats 

 of anti-corrosion. 



Green paint is the most expensive of all 

 colours, and has little body to protect 

 the timber. For hothouse - work it 

 should never be used, unless to paint, as a 

 finishing-coat, plant-boxes for oranges and 

 similar large plants — and then the hoops 

 and handles should have two coats of 

 anti-corrosion ; and if of a light stone 

 colour, it will contrast with the green of 

 the other parts : but, even for this purpose, 

 we prefer painting the hoops and handles 

 black. 



White-lead paint. — This is the most 

 generally used of all paints ; it has suffi- 

 cient body to preserve the timber, and 

 may be compounded of different shades. 

 Pure white, as a colour, may be used for 

 the interiors of hothouses, as being the best 

 reflector of light, but not for the exteriors, 

 as it becomes so soon stained with smoke 



