Three copies of a Letter, dated November 5, 1936, from Sister M. Monica to Sister Mary Gonzaga, relating to her the benefits of using scalebuoys in the water to the boilers and hot water systems. It had removed scale from the pipes. The only problem they had was the scale that had fallen off blocking the traps and that soon stopped. Scalebuoys were going to be installed in the cold water system as soon as there was more money to do it.Letterhead -St Josephs Hospital Phoenix Arizonasciences, instruments - general, scalebuoy, bill ashman collection - correspondence, st joseph's hospital arizona, sister mary gonzaga, mater misericordiae hospital auckland, mr herzog, st mary's hospital san francisco, mr abbott, sister mary monica