5o8 



POPULAR SCIENCE MONTHLY 



sented as nearly as practicable the con- 

 ditions existing in the actual use of 

 steam pipes. Of sixteen non-conduct- 

 ing preparations tried, the most efficient 

 were found to be those made of cork; 

 next was a cover composed of an inner 

 jacket of earthy material and an outer 

 jacket of wool felt; and next magnesia. 

 In reference to the last substance it is, 

 however, observed that, while it is a 

 most effective non-conductor, the name 

 has been applied to many compounds of 

 which the greater part consist of car- 

 bonate of lime or plaster of Paris, mate- 

 rials which are not good as heat retard- 

 ents. Asbestos is merely a non-combus- 

 tible material in which air may be 

 entrapped, but, when non-porous, is a 

 good conductor of heat. Generally 

 speaking, a cover saves heat enough to 

 pay for itself in a little less than a year 

 at three hundred and ten ten-hour days, 

 and in about four months at three hun- 

 dred and sixty-five twenty-four-hour 

 days. The decision as to the choice of 

 cover must, however, come from other 

 considerations, as well as from that of 

 non-conductivity. Ability to withstand 

 the action of heat for a prolonged period 

 without being destroyed or rendered less 

 efficient is of vital importance. The 

 cork coverings were found to respond to 

 this test extremely well, and there can 

 be no question respecting magnesia; but 

 Mr. Norton does not consider it safe to 

 put upon a steam pipe wool, hair, felt, 

 or woolen felt in any form, though the 

 danger is not likely to accrue when an 

 inch of fireproof material stands be- 

 tween the felt and the pipe. In general 

 it may be said that if five years is the 

 life of a cover, one inch is the most eco- 

 nomical thickness, while a cover which 

 has a life of ten years may to advantage 

 be made two inches thick. The method 

 of judging a pipe cover by the warmth 

 felt on putting the hand upon it is fal- 

 lacious; the sensation depends so much 

 upon the nature of the surface that it 

 utterly fails to give any idea of the 

 actual temperature. 



Effect of Sea Water on Soil. — In 



a paper read at the liritish Association, 

 1899, on the chemical effect of the salts 

 of the salt-water flood of November 27, 

 1897, on the east coast of England, 

 Messrs. T. S. Dymond and F. Hughes re- 

 corded the remarkable result that, al- 



though the proportion of salt left in the 

 soil was insufficient to prove injurious 

 to growing crops, the earthworms were 

 entirely removed, with the consequence 

 that very few crops were worth harvest- 

 ing the following year. In the next year 

 nine tenths of the salt at first present 

 had disappeared from the soil, and 

 young worms had again made their ap- 

 pearance, but still the condition of the 

 soil remained unsatisfactory, the rate 

 of percolation of water through the 

 flooded earth being only one half as 

 rapid as through the unflooded. The 

 authors ascribe this to the action of the 

 chlorides of the sea water on the sili- 

 cates of the soil with the formation of 

 silicate of alumina in a gelatinous con- 

 dition. 



The War against Monopolies. — 

 Mr. Eobert Ewen writes, in the West- 

 nunster Eeview, demanding free bank 

 circulation as likely to be a very effect- 

 ive weapon to be used in " the coming 

 contest with monopolists." The subject 

 seems to have attracted official atten- 

 tion in England in 1875, when Sir Staf- 

 ford Northcote was Chancellor of the 

 Exchequer. As chairman of the com- 

 mittee appointed to inquire into the 

 working of the Bank Acts, he submitted 

 a memorandum showing that, while cer- 

 tain items of the monopoly enjoyed by 

 the Bank of England had been with- 

 drawn, a residuum of restrictions on 

 issuing banks still remained unrepealed. 

 Some other countries have found a way 

 of giving elasticity to the cuiTcncy by 

 buying in and laying aside their bonds, 

 as the United States has recently been 

 doing. This can not be done in Great 

 Britain, because the Bank of England 

 and the other bank monopolists block 

 the way. The bank is tied down by 

 acts of Parliament to buy and sell gold 

 at a fixed price, and this restriction has 

 been a cause of panics, whereas had gold 

 been allowed to rise and fall in price, 

 according to supply and demand, and 

 the bank got a free hand in dealing with 

 that commodity and in issuing legal 

 notes to supply the circulating medium, 

 " all would have gone well." Foreign 

 protectionists now have the power to 

 prevent British goods from getting into 

 their markets by imposing heavy duties 

 on them, and at the same time forcing 

 tlioir produce into British markets, be- 



