90 The Phosphates of America. 



arrangement of their plant, which we have endeavored to broadly 

 outline in our illustration on opposite page, and at which a critical 

 glance will be interesting. 



Acid Chambers. The subject of chamber construction is well 

 worn, if not exhausted ; their form and size have long been bones 

 of contention over which certain wiseacres, with plenty of time for 

 useless discussion, have growled ad nauseam. After a very varied 

 experience and careful inspection of many working systems, we 

 have concluded that the required object i.e., the proper conden- 

 sation of the gases can take place equally well in one large cham- 

 ber as in a series of two or three, and that a choice of either is 

 essentially a matter of personal taste and personal opinion. A 

 very excellent arrangement will be found to consist in a set of 

 two, adopting as favorable dimensions 125 feet long by 24 feet 

 wide and 18 feet high. The connections are made by a fifteen to 

 eighteen inch diameter lead pipe hung from the roof, with a good 

 fall at its end to prevent the accumulation of 'any condensed acid. 



As to the necessary thickness of lead, there is almost as much 

 diversity of opinion as upon the dimensions of the chambers ; but 

 remembering that a good chamber, properly started and soundly 

 built, should last from ten to twelve years, a happy medium may 

 be attained in this direction by adopting seven-pound lead for the 

 first and six-pound for the second. 



The amount of chamber room should in no case be less than 

 20 cubic feet for every pound of sulphur consumed. 



The pressure of steam should be as evenly distributed as possi- 

 ble, and the faulty system sometimes adopted of introducing it 

 from a single jet, which can only play upon one portion of the 

 gases, must be carefully avoided. Since of every 100 tons of 

 chamber acid produced one-half consists only of water originally 

 injected in the form of steam, it has been urged by Dr. Sprengel 

 that this warm steam unnecessarily expands the bulk of the gases, 

 instead of lowering their temperature, and causing them to shrink 

 in volume. 



To obviate this inconvenience he has therefore suggested the 

 use of a spray of cold water, to be forced into the chamber by a 

 pump of his own invention ; but the device, while ingenious, does 

 not work well and has not been generally adopted. 



The preferred method is to inject steam into the entrance end 

 of the chamber and into its side rather more than half the way 

 along. 



