VARIETIES.

Effects of Colouk upon Health.?From several years' observations iu rooms of various sizes, used as manufacturing rooms, and occupied by females for twelve hours per da}r, I found that the workers who occupied those rooms which had large windows with large panes of glass, in the four sides of the room, so that the sun's rays penetrated through the room during the whole day, were much more healthy than the workers who occupied rooms lighted from one side only, or rooms lighted through very small panes of glass. I observed another very singular fact?viz., that the workers who occupied one room were very cheerful and healthy, while the occupiers of another similar room, who were employed on the same kind of work, were all inclined to

melancholy, and complained of pains in the forehead and eyes, and were often ill and unable to work. Upon examining the rooms in question, I found they were both equally well ventilated and lighted. I could not discover anything about the drainage of the premises that could affect the one room more than the other ; but I observed that the room occupied by the cheerful workers was wholly whitewashed, and the room occupied by the melancholy workers was coloured with yellow ochre. I had the yellow ochre all washed off, and the walls and ceilings whitewashed. The workers ever after felt more cheer- ful and healthy..? Correspondent of the Builder.

Air-Poison.?People have often said that no difference can be detected in the analyzation of pure and impure air. This is one of the vulgar errors diffi- cult to dislodge from the public brain. The fact is, that the condensed air of a crowded room gives a deposit which, if allowed to remain for a few days, forms a solid, thick, glutinous mass, having a strong odour of animal matter. If examined by the microscope, it is seen to undergo a remarkable change. First of all, it is converted into a vegetable growth, and this is followed by the production of multitudes of animalcules ; a decisive proof that it must contain organic matter, otherwise it could not nourish organic beings. This was the result arrived at by Dr Angus Smith, in his beautiful experiments on the Air and Water of Towns; wherein be showed how the lungs and skin gave out organic matter, which is in itself a deadly poison, producing headache, sickness, disease, or epidemic, according to its strength. Why, if

" a few drops of the liquid matter, obtained by the condensation of the air of a foul locality, intro- duced into the vein of a dog, can produce death with the usual phenomena of typhus fever," what incalculable evil must it not produce on those human beings who breathe it again and again, rendered fouler and less capable of sustaining

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life with each breath drawn ? Such contamination of the air, and consequent hot-bed of fever and epidemic, it is easily within the power of man to remove. Ventilation and cleanliness will do all, so far as the abolition of this evil goes, and ventilation and cleanliness are not miracles to be prayed for, but certain results of common obedience to the laws of God.?Dickens's Household Words.