THIRTEENTH ANNUAL MEETING. 



91 



well ; in another it did, and killed the scale fairly well, but it 

 is a comparatively expensive material. Here is a sample of 

 the fused sulphide of soda which I have mentioned. [Exhibited 

 specimen of sulphide of soda, price 2^ cents a pound.] In this 

 lump form you cannot use it very well ; but you can buy it from 

 the Adler Chemical Company, who promise to grind it at a small 

 expense, making- it cost slightly over 3 cents a pound. We find 

 it somewhat hard on the hands. I believe it to be a promising 

 thing, and one that is worth testing, but it is too early to recom- 

 mend it in a general way. 



I should not advise any great outlay of apparatus for boiling. 

 I think we can get rid of boiling after two or three years more 

 experimenting. It is a very simple matter to hire a portable 

 boiler for a few days. It is not necessary to have iron pipes. 

 Have your connections and valve, and screw on rubber hose 

 and run into the barrel. Have it so that you can shut it off from 

 an}' particular tank. Use some piece of worn-out rubber hose. 



Baron Von Herff : I do not think it would be necessary to 

 use a steam boiler. The solution can be boiled in iron kettles. 

 Much less water would be more economical than to use twenty 

 gallons of water — half a barrel. 



Prof. Brittox : I intended to say a third of a barrel. We 

 think it dissolves faster than with a very little. 



Baron Von Herff: I think one-sixth of a barrel boiled with 

 the lime and sulphur would be cheaper. It is well known that 

 chemical combination takes place more readily in concentrated 

 solutions. The converting of the sulphur into sulphides takes 

 place more readily. What you want is not free lime, but sul- 

 phide ; the chemical combination of the two is what is effective. 

 It does not kill the scale outright, but some of it settles in the 

 crevices of the bark. It remains there, and it is probable that 

 in course of time sulphuret of hydrogen develops, which kills 

 the young scale. The ordinary caustic sodas will not take the 

 place of this solution. They do not develop anything, — they 

 kill by contact. They may kill the scale where they touch it, 

 but the}'' will not suppress the scale. It is quite possible to mix 

 this lime and sulphur beforehand and keep it in a solid con- 

 dition and use it whenever you get ready. It forms crystals 

 which can be kept, and }ou can dissolve these. Any one can 

 prepare it by making this mixture rather concentrated. It will 

 form crystals which can be kept and used later on. 



