Septembeb 11, 1908] 



SCIENCE 



327 



stones are liable to crack from heat if still- 

 ing is pushed too hard, and, of course, the 

 lead and porcelain parts of the apparatus 

 give out repeatedly. 



In making sulphuric acid by the cham- 

 ber process, the chambers of course are 

 entirely made of lead; but as nitric acid 

 and nitrogen oxides are mixed with the 

 sulphur dioxide gases the strength of sul- 

 phuric acid in the chambers can never be 

 allowed to fall below 45° ; otherwise it will 

 dissolve nitric acid in sufficient quantity to 

 attack the lead very rapidly. If, on the 

 other hand, the strength in any chamber 

 is allowed to go above 55° nitrogen oxides 

 are dissolved which also attack lead. Be- 

 tween 45° and 55° strength, however, 

 almost no nitric acid or nitrogen oxides 

 are dissolved and the chambers are safe. 

 The action of nitric acid on lead cham- 

 bers is very insidious and its affects are 

 difficult to detect until a hole finally 

 comes through the lead, probably simul- 

 taneous with the descent of several tons of 

 acid. 



I might go on to discuss acid eggs, 

 pumps, sprays, piping, tower filling and 

 tanks of a sulphuric-acid plant. In every 

 one of these a careful consideration of the 

 strength and temperature of acid is neces- 

 sary before we can determine what ma- 

 terials are best or are even to be considered 

 in its construction. I might go on to 

 other industries and discuss why, for in- 

 stance, in C.P. acids we are reduced 

 to the use of glass, porcelain or platinum, 

 while for C.P. ammonia iron is perfectly 

 permissible, and for pure acetic to be 

 used for vinegar none of these will do 

 (except possibly glass), but we must use 

 silver. Go through every branch of chem- 

 ical industry, undertake to transport any 

 chemical reaction from a laboratory to a 

 works, and the very first problem that 

 confronts you is what material to use in 

 making your apparatus. The thing I want 



to impress on you is that you can not 

 make a chemical, you can not make a 

 thing in a chemical works without some- 

 thing to make it in, and the choice of that 

 something is exceedingly important and 

 worthy of serious consideration. 



The next line upon which I would recom- 

 mend the young chemist to be better 

 equipped than chemists usually are, is in 

 his knowledge of power accessories and 

 transmission machinery. I do not mean 

 that he should have any extensive knowl- 

 edge along these lines, but he should cer- 

 tainly know the principles of a steam 

 engine, how to start and stop it and when 

 it is running properly. He should know 

 the principles of boiler construction and 

 boiler setting and how to care for a boiler ; 

 what amounts of fuel can be burned on a 

 given grate surface, what evaporation may 

 be expected from this fuel, and what power 

 it will furnish, and what temperature and 

 analysis of flue gases may be considered 

 economical operation. He should know 

 about steam pumps, their valve arrange- 

 ment and how to compute their capacity 

 under various pressures. He should know 

 centrifugal pumps and under what circum- 

 stances they may be used; blowers plus 

 pressure blowers and exhausts, mechanical 

 stirring apparatus, shafting and pulleys 

 and how to place them. By all this I do 

 not mean that he should be an expert in 

 factory design, or even a millwright or 

 pipe fitter, or engineer or stoker, although 

 he would certainly be much better equipped 

 if he did have all these accomplishments. 

 Yet all these things I have mentioned are 

 the very tools of his trade, they are his 

 beakers, and bunsen burners, and suction 

 pumps, and stirring rods and steam-baths. 

 If the young chemist gets on at all in 

 manufacturing or using chemicals he must 

 use all these appliances, and men working 

 under his direction must manipulate them 

 all, so it seems to me the part of wisdom 



