564: Transactions. — Chemistry and Physics. 



subjected to a high temperature would be rendered easier 

 by a determination of the electric conductivity of various 

 specimens. 



Art. LIV. — Analyses (Technical) of New Zealand Coals. 

 By Dr. W. P. Evans. 



[Read before the Philosophical Institute of Canterbury, 2nd November 



1898.] 



Methods used in deterviining the Given Quantities. 



1. Water. — Coal (3 gr. to 6 gr. in platinum boat) heated 

 in toluol bath* (107° C.), in current of dry coal-gas, and water 

 given off absorbed in weighed chloride of calcium tube. Time 

 of heating, three hours. 



2. Ash. — The dry coal, from water-determination, heated 

 in platinum boat over flat Teclu burner till of constant 

 weight. 



3. Sulphur. — Eschka method, spirit flame only being 

 used ; checked where result seemed abnormal by Carius 

 method. 



4. Coke. — Muck's normal test in closed platinum crucible 

 over free Bunsen flame. f Heating continued for thirty 

 seconds after disappearance of luminous flame. 



5. Heating Effect. — The values given are calculated ac- 

 cording to a formula suggested by the American Coal Analysis 

 Committee in their prehminary report. | As the heating 

 values of coals Nos. 1-10 had previously been directly deter- 

 mined by means of a Hempel calorimetric bomb, I was able 

 to compare the values given by the formula with those 

 obtained by absolute combustion. As these values, together 

 with other details regarding coals Nos. 1-10, will shortly be 

 published, I need here only remark that the American 

 formula gives very good results for the hard coals (1-5), but 

 that in the case of the brown coals (6-10) the values, though 

 in the same relative order as those determined by actual com- 

 bustion, are not so widely differentiated. 



* Trans. N.Z. Inst., vol. xxx., p. 495. 

 •f Muck, " Sceinkohlenchemie," p. 8. 

 X Chem. News, 1898, p. 75. 



