102 Proceed vngs of the Royal Society of Victoria. 



On account of the great and obvious convenience for this pur- 

 pose, another attempt was made to use thermal junctions to 

 measure the difference of temperature between the in- and 

 out-flowing stream. It was imjDOssible to use a delicate ther- 

 mometer, with its large bulb, in a satisfactory way to measure 

 the temperature of so small a stream of water, and further, the 

 thermal junction could be pushed down the end of the tube just 

 far enough to give the temperature inside the spiral at the very 

 point where it entered or left the surface of the water in the 

 calorimeter. But repeated attempts at accurate calibration only 

 gave in inconsistent results, and the use of thermal junctions and 

 with it of this method of working had to be abandoned for the 

 time being in favour of a method that now suggested itself, in 

 which delicate mercurial thermometers could be used throughout. 

 Nevertheless, I am still inclined to think that the above mode of 

 working, combined with an electrical resistance method of 

 measuring temperatures is likely to give results as good, and 

 possibly better than those actually attained with the method 

 next to be described. 



The same calorimeter, glass spiral tube, stirrer, etc., were used 

 for this method, but the experiment consists in simply running 

 into the spiral tube a quantity of hot water sufficient to fill all or 

 nearly all of that part of the tube which is immersed in the 

 liquid of the calorimeter. The liquid whose specific heat it is 

 desired to measure may be used either in the calorimeter — and if 

 400 cubic centimetres are obtainable this is the more desirable 

 course — or else pure water may be placed in the calorimeter and 

 the experimental liquid may be heated and run into the spiral. 

 In either case an experiment is first made with pure water, and 

 the calculations become very simple. 



If $1 be the temperature of the hot liquid 



9q be the initial temperature of the liquid in the calorimeter 

 6 be the maximum temperature of the liquid in the calorimeter 

 Wj be the weight of the hot liquid run into the spiral 

 Wfl . - . . . liquid in the calorimeter 

 and o-j and o-q their respective specific heats ; then, if 



W be the water - equivalent of the entire calorimeter and 

 its contents, we have 



w,(^i-^)t, = W(^-^o) - - - - (/) 



