The Prcvcntio)i of Formation of Scale in Boilers 



349 



of all slimy substances. In boilers of some- 

 uhat complicated construction, they collect 

 upon parts where the water boils least, adher- 

 ing there readily to the boiler; and since the 

 water attains through them a higher specific 

 gravity and produces scum, they are readily 

 thrown into the steam pipes and engine cy- 

 linders. In spacious and simple boilers, they 

 may, however, render good service. 



Fatt)' bodies and tar serve to diminish ad- 

 hesion. Spermaceti oil alone, according to 

 Bedford, gives good results. It has been re- 

 commended to cover the tubes and parts ex- 

 posed to the fire with a mixture of 3 lb. 

 graphite powder and 18 lb. molten tallow. 

 Newton communicated a recipe for a mass, 

 which is said to adhere still better. It con- 



sists of 8 parts tallow or lard, which is first 

 mixed with 8 parts fine graphite (plum- 

 bago), and then well kneaded with i part fine 

 charcoal powder, while warm. When it is to 

 be applied, the mass is rubbed together with 

 oil or gas tar. In applying these proposed 

 remedies, it is not to be overlooked that, al- 

 though only small quantities of gas and tar 

 are rendered volatile by the steam, they may 

 at times become troublesome. Some deny 

 their efficiency entirely, maintaining that scale 

 is formed wherever surfaces are directly ex- 

 posed to the fire ; but others say that this 

 scale is more easily detached. There is here 

 a large and highly remunerative field for in- 

 ventors, and we hope it will not long remain 

 unexplored. 



