10 



TiMEHRI. 



Will some one explain why these light gases are not 

 given off earlier in the career of the juice, when its tem- 

 perature is higher, and its density is lower ? 



Data taken by the writer in 1888, immediately after 

 ere6ling the first " Yaryan" evaporator in this colony, 

 will be interesting when compared with data taken after 

 the addition of another vessel, converting it from a 

 quadruple into a quintuple effet ; also data taken from a 

 triple. It is well worth noting that in each case the 

 greatest difference of temperature was in the last vessel : 



One gathers from Mr. CORNISH'S letter that he be- 

 lieves circulation prevents corrosion ; with soft scales 

 this is correct but with the hard scales here dealt with, 

 circulation appears to have little effect in preventing 

 deposit; for instance "Yaryan" and other film evapor- 

 ators scale quite as quick as ordinary evaporators. To 

 prevent scaling, what appeared to be a very good practi- 

 cal suggestion was made in Sugar Cane some time 

 back, viz., to insert a wooden lath into each tube for 

 the scale to deposit on. This lath at the same time 

 by displacing much idle liquor facilitated circulation, and 

 consequently increased the evaporation per square foot 

 of heating surface. Of course if this was applied to a 

 vertical evaporator means would have to be taken to 

 prevent these wood laths from floating out whilst at the 

 same time facilitating their withdrawal. The writer has 

 some under observation at the present moment. As a 

 matter of fa6t a spanner inadvertently left in a calandrie^ 



