411 



not ill the case of tlie coarse-granular ore at the foot of this hilP)". 



This assertion is apparently foniided on (he fact ihat fin-ore is 

 one of the minerals that are diflicnlt of fusion, but that it is easily 

 reduced to tin by the addition of charcoal. This assertion does not 

 satisfy us any more than Vekmaes's pronouncement that "there is no 

 doubt but that the tin-ore is reduced to ?/^^i'r//", by means of a burning 

 pile of wood. An experiment does not seem to have ever been made. 



The melting point of tin-ore as established by R. S. Cusaok at 

 1127° C. ^), seems to me to be too low, as higher points are found ') 

 for much more fusible minerals, e. g. for augite 1100° — 1200° 

 (according to C. Doet.ter *)) and for plagioclases (labradorite to 

 oligoclase) 1130°— 1300° ^). Anyhow Cusack's melting point (1127°) 

 being even higher than the heat produced by the burning of 

 living wood — the only wood we have to deal with — it is obvious 

 that a burning wood cannot reduce lin-ore to tin. Moreoxer, whereas 

 alang-alang fires may occur repeatedlj' every year towards (he close 

 of the West-monsoon, foi-est-fires are decidedly the exception, so 

 that even on this account the recpiired amount of tin could not have 

 been produced in this way. 



Furthermore, it still remains to be seen whether the expected 

 result can be obtained even at high temperatures. In modern mine- 

 ralogical textbooks and manuals — with a few exceptions — the 

 hypothesis is advanced that tin-ore does not undergo any change, 

 when the blowpipe is applied. This squares entirely with the results 

 most inquirers are capable of achieving in connection with (he 

 difficulty of mastering some facility in handling the blowpipe. Years 

 ago Berzklius wrote: "Das Oxj-d verandert sich und schmilzt nicht, 

 aber von einem starken und anhaltenden Reduktionsfeuer kann 

 reines Zinnoxyd ganz und gar ohne Zusatz zu Zinn reducirt werden. 

 Dies erfordert indessen eine Gewohnheit das Löthrohr zu gebrau- 

 chen."*') This is in character with C. F. Plattner's opinion, who, 



1) Bangka, beschreven in reistochten. Amsterdam 1865, p. 68. 



•) On the melting points of minerals. Proceed. R. Irisli Acad, of Sc. (3) 4. 

 Dublin 1896—98, p. 413. 



8) Beziehungen zwischen Schmelzpunkt und chemischer Zusammenselzung der 

 Mineralien. Tschermaks Miner, petrogr. Miltlg. 22. Wien 1903, p. 399—311. 



*)G. DoELTER, Handbuch der Mineralcliemie. 1. 1912, p. 663. 



6) The above mentioned melting-points are somewhat too low. as the author 

 himself has acknowledged afterwards (Handbuch der Mineralcliemie 2. 1. Dresden - 

 Leipzig 1914, p. 579). 



8) Von der Anwendung der Löthrohrs in der Chemie und Mineralogie. Ueberselzt 

 von H. Rose. Niirnberg 1821, p. 113 — 114. At present it is extremely difficult 

 to ascertain whether any writer before Bebzelius has obtained the same result. 



