614 



PROCEEDINGS OF SECTION H. 



Appendix No. 2 — continued. 



Accompanying this appendix is a transverse section through the- 

 water jacket and tubes of the Shann boiler. 



Steam users are well aware that there are many factors which 

 must be considered before pronouncing a boiler economical or 

 otherwise. 



Many of the most efficient boilers are but litle used owing to 

 their exorbitant first cost. To form an opinion of the relative 

 cost of the Shann boiler and another favorite and economical 

 boiler the writer paid a visit to one of the leading firms in 

 Melbourne and got quotations for a boiler of the same rating as 

 that just tested ; the quotations were more than twice the price Mr. 

 Shann informed him that his boiler had cost, and, further, when 

 the boiler was delivered to the purchaser he would have the expense 

 of building it in an elaborate brick seating. This boiler also would 

 weigh two and a half times as much as the former, and would not 

 admit of being forced to a greater extent than 50 per cent., 

 whereas the Shann boiler can easily be forced beyond 100 per 

 cent, without any diminution in efficiency. 



The second most important question is whether the boiler is 

 economical in maintenance. Of course in a new type of boiler it is 

 not easy to predicate exactly what the maintenance will cost. How- 

 ever, so far water tube boilers have not been found more expensive 

 on this head than other boilers, and owing to its strong and well 

 braced construction, which is sufficiently elastic to allow for any^ 

 conceivable alteration from expansion, and to take iqD any jar or 

 shock it may encounter, there is every reason to anticipate that 

 his boiler will be cheap in maintenance. The third important 



