OCTOKER 13, 1922] 



SCIENCE 



425 



fieations of instruments used in automatic process 

 control: first, indication; second, recording, and 

 third, controlling. Indicating tj'pes of instru- 

 ments are used in determining experimentally and 

 in actual production the exact temperature and 

 pressure specifications to follow to obtain higher 

 quality and maximum production at a minimum 

 cost. Eeeording types of instruments are used to 

 maintain continuous and permanent records of 

 these readings, which records may then be filed 

 for future reference. Controlling instruments are 

 used to control these temperatures and pressures 

 automatically. In this way there is the assurance 

 of duplicating results. In many oases only by 

 automatic control can certain temperature or 

 pressure specifications be followed exactly. 



Some pliases of automatic process control: 

 Herbert A. Claek. Process control during the 

 initial stages of the development of the process 

 is usually a matter of close observation on the 

 part of the operator and careful hand adjustment 

 to meet conditions as they arise. When the steps 

 become known, the process is standardized and 

 the control is made automatic as far as prac- 

 ticable. If the desired control is merely to keep 

 the temperature constant, some type of thermo- 

 stat is employed. Where the temperature must be 

 varied in a predetermined way over a certain 

 length of time, au instrument has been devised 

 which automatically varies the temperature of the 

 container at any desired rate, either constant or 

 variable; holds the temperature at any point be- 

 tween certain limits for any desired time; re- 

 moves the condensation in case of steam-heated 

 apparatus; cools the container at any desired 

 rate at the end of the process; stops the process 

 at any desired point, and signals this fact to the 

 operator. 



Hydrogen ion methods as applied to process 

 control: Eakl A. Keller. The increasing use of 

 hydrogen ion measurements in the laboratory has 

 opened a field for such methods in automatic 

 process control. A brief description of an instal- 

 lation is given. Other automatic control methods 

 utilizing electrical measuring apparatus have 

 already been applied successfully, such as the 

 temperature controller in oil-refining processes 

 and in the making of illuminating gas. Electro- 

 lytic conductivity equipment has also proven very 

 useful. The value of process control by signal 

 indicating apparatus with manual operation is 

 compared to control that is entirely automatic. 

 A brief description is given of the conductivity 

 equipment used for salinity measurements on 

 battleships. A new method for measuring and 



controlling turbidity is described, based on the 

 characteristics of a photo-electric cell. 



Cost accounting as a factor in the control of 

 chemical processes: Charles Wadsworth, 3d. 

 Once accurate costs are obtained, they must be 

 deftly used. There are many pitfalls for the 

 executive who places blind allegiance in cost 

 figures. Close contact with manufacturing plants 

 is essential, and an understanding of manufac- 

 turing problems and manufacturing psychology is 

 sine qua non. An intelligent limit can be placed 

 on purchasing, prices and wages. The efficiency 

 of each step in complicated manufacturing 

 processes can be isolated, controlled and made 

 more efficient. The. knowledge of whether a 

 product is making money or not enables the 

 executive to control production and sales, espe- 

 cially as to quantities, and to direct emphasis to 

 the most profitable enterprise. As the most accu- 

 rate indicator of business health, technical men 

 must become accjuainted with cost procedure, 

 unless they are willing to remain in positions 

 subordinate to men with business training who 

 understand cost procedure. 



The removal of small amounts of CO from gases 

 Tiy passage through heated granular soda lime: 

 Egbert E. Wilson, C. A. Hasslacher and E. 

 Masterson. The problem of the complete re- 

 moval of CO from gas streams is of importance 

 in a number of industrial applications, particu- 

 larly in the purification of hydrogen and nitrogen 

 for the synthesis of ammonia. Several references 

 and patents have mentioned the use of soda lime 

 at high temperatures for the purpose, but prac- 

 tically no quantitative data is offered with regard 

 to the removal of small amounts or the effect of 

 the composition of the soda lime. This paper 

 describes a series of experiments on gas contain- 

 ing 2 per cent. CO in N2 at temperatures varying 

 from 250° to 550° and using soda limes of vary- 

 ing composition. The results show that soda 

 lime with high caustic soda contents are better 

 than those too low, or than lime alone. The 

 former give substantially complete removal of 

 CO at around 400° C. Small amounts of moisture 

 are helpful in increasing the efficiency but do not 

 appear to be essential. Experiments in the pres- 

 ence of hydrogen are inconiclusive because the 

 hydrogen reacted slightly with the I2O5 used to 

 determine CO. The fundamental reaction involved 

 is apparently CO + 2NaOH = NagCOg + Hg. 



Tlie calculation atid comparison of specific rates 

 of corrosion in natural waters: Sobert E. Wil- 

 son. The writer makes use of the fact that cor- 

 rosion in practically all natural waters at tem- 



