Decay of Oaspijpes in certain Soils. 21 



our instance we cannot apply the views of Berzelius, for 

 protoclilorideof iron sweating out of the pores of our pipe shows 

 that the chlorine is implicated. Moreover, the Cranbourne 

 meteorite, that known as Bruce's, sweated drops of chloride of 

 iron, and showed on the outer surface symptoms of having 

 suffered a considerable wasting by oxidation. The sweating 

 and the rusting are, in the particular instance, connected by 

 the fact that the drops of iron chloride solution, coming out 

 from newly-polished artificial surfaces of the metal, rapidly 

 corroded the surface, forming a crust of oxide of iron. In a 

 letter received from England, it is stated that Professor 

 Maskeleyne had expressed concern as to the futm-e of the 

 Bruce meteorite, on account of the decay to which it 

 appeared subject. In the gaspipe and in the meteorite, two 

 very difierent instances, we have the presence of iron proto- 

 chloride accompanying, and apparently the disposing agent 

 in effecting the passage of iron from the metallic state to the 

 state of oxide. 



It appears that the decay of cast-iron mains,' due to salt in 

 the soil, has been noticed elsewhere. Dr. John Smith, 

 professor of chemistry in the Sydney* University, has men- 

 tioned to the wiiter of this note a case occurring in India in 

 which the mains, water-pipes it is believed, laid in swampy 

 salt ground, perished so rapidly (in a few years in fact) that 

 the engineer employed on the question proposed as the best 

 remedy the use of steel mains laid in air, supported on piers. 

 It was calculated that the additional strength of the proposed 

 material over that of cast iron would allow of the use of steel 

 pipes of so light a substance that their cost would not greatly 

 exceed that of the quickly-perishing cast iron. 



In the recent commission for inquuy concerning the City 

 of Sydney Water Supply, this property of salt soil has not 

 been overlooked — indeed the occurrence of salt ground has 

 been regarded as a cog-ent reason against what might 

 otherwise have been material to a practicable scheme lor a 

 high-level service. 



That gas and water mains of cast-iron will, under ordinary 

 circumstances, last in the ground for a great number of 

 years is established by a wide experience, but that cases of 

 an opposite nature occur is shown by the example brought 

 forward. The writer has no personal knowledge concerning 

 the average " life " of water and gas mains, but he observes 

 in the little treatise on " Gasworks," by Hughes, that 1-?,- per 

 cent, has been allowed for this deterioration in the case of 



