Document YGwY69aYNkJB1z4qKQgN4qRmN

:3'13 x lines coniz e the free ( 950) gives t filial silica >< -auoi s arc e ial is sub- alcin ution. blac lilead) efle x of idt an equal xganufi cture of c irbon uk hol'Urever. nateri il for nd p PNEUMOCONIOSIS OUf TO GRAPHITE ANIJ SOOT )05 Manufacture of artificial graphite Artificial graphite is prepared by crushing, grinding and calcining of gas and oil cokes, and is used in the manufacture of shaped carbon blocks and electrodes for use in electric furnaces in the production of aluminium metal This material is a very pure form of carbon, and the silica content seldom exceeds 1 per cent of the total weight. It has been proved, and accepted for purposes of Industrial disablement benefit, that labourers employed In the milling operations suffer from pneumoconiosis similar to that found among workers in natural graphite. In Great Britain, soot, lamp-black or " nearly pure carbon " is manu factured commercially by the incomplete combustion of gas and tar oils and petroleum distillates Mineral impurity constitutes only a trace. The chief uso of this product is us a reinforcing filler in rubbor-compounding. Tn addition to producing rigidity in the vulcanized rubber, the carbon increases the tensile strength and the resistance to abrasion. No definite evidence of pneumoconiosis, in either the lamp-black or the rubber industry, has so far been recorded in Great Britain, but Brauss and dinner (1951) have recorded tho occurrence of cases in Germany. A similar product--gas-black-is manufactured in America by burning natural gas, which is 95 per cent methane. This work, it is reported, does not cause any pulmonary disease. Recently the writer has observed a few cases of simple pneumoconiosis among a group of workmen in the north of England who were engaged for many years (30 to 50) in the manufacture of soot (no silica impurity). Cause of coal and graphite pneumoconiosis These observations arc important in relation lo the aetiology of pneumo coniosis of coal-workers The problem is whether these cases of pneumo coniosis arc due to the small amount of silica within the coal or graphite or are due to the carbon itself. That thcro is no simple answer to this question will be realized, if one recalls that the pathological changes in the lungs may be determined, not only by the quality of the dust, ohemical and physical, but also by mere quantity of fine particles, while both factors may be further influenced by associated infection ASBESTOS1S Asbestos, meaning unconsumable, is a collective term applied to a group of silicate materials, which, while differing widely in chemical composition, resemble each other in certain valuable physical properties. They are finely fibrous in structure, and so can be split readily to microscopic size without loss of identity. Single fibres have been noted up to 43 inches and down to 0-000003 inch in longth. The fibrous structure, which, in varying degree, is associated with flexibility, enables it to be spun into yarn and then woven % 'ib