July 3, 1914] 



SCIENCE 



37 



A brief survey of the field with special reference 

 to the difficulties encountered in correlating the 

 chemical and structural analyses of malleable cast 

 iron in the hard and in the annealed states. 



The Pyrometer in the Assay Muffle: Feederic P. 



Dewet. 



Standing alone, by itself, a pyrometer reading 

 has absolutely no value as a control of assay 

 operations in a mufSe or as a guide to the assayer 

 in carrying on such operations. The reasons for 

 this are varied and complex. In the first place, the 

 temperature that controls the success of the oper- 

 ation is that of the lead button undergoing oxida- 

 tion. At present we have no means of learning 

 this temperature under practical working condi- 

 tions, so that some suitable place must be selected 

 within the muffle for the location of a pyrometer. 

 Unfortunately, however, and in the second place, 

 there is absolutely no approach even to a fixed re- 

 lation between the pyrometer reading at any given 

 point available and the temperature of the oxidiz- 

 ing button. The oxidation of the lead supplies 

 much heat to the button, but its effect upon the 

 pyrometer is negligible. One factor governing the 

 amount of heat utilized by the button is the rate 

 of oxidation of the lead, and this in turn is, within 

 wide limits, largely influenced by the passage of 

 the air over the button, so that to fully utilize and 

 apply the pyrometer reading we must also know 

 the height of the barometer and the effect of varia- 

 tions in the barometer readings upon the draft of 

 the particular muffle under consideration. Further 

 and most important, from a practical standpoint, 

 is the freedom of entrance for the air to the 

 muffle. In other words, by manipulating the door 

 or stopper of the muffle, widely varying differences 

 between the button temperature and the pyrometer 

 reading may be produced. The effect of the door 

 condition is twofold. It affects the supply of air 

 to the button and also the actual temperature of 

 the bottom of the muffle on account of varying 

 amounts of air that have to be heated there in 

 passing through the furnace. Finally, the relation 

 of the position of the button within the muffle to 

 that of the pyrometer is vital. Therefore, to in- 

 telligently utilize any stated pyrometer reading it 

 is essential to have exact information upon a va- 

 riety of other conditions surrounding the opera- 

 tion. However, the pyrometer is a good general 

 guide to temperatvire conditions, but the man who 

 depends upon it entirely will not be a good cupeller. 



Note on a Cause of Spontaneous Combustion in 

 Coat Mines: Horace G. Portek. 



Graphical Studies of the Vltimate Analyses of 



Coals: Oliver 0. Ealston. 



Plotting the ultimate analyses of coals, in terms 

 of carbon, hydrogen and oxygen, on the ' ' ternary 

 diagram ' ' as modified to compensate the greater 

 errors involved in the term ' ' oxygen, ' ' has given 

 results of surprising concordance. Some thou- 

 sands of analyses are plotted with different ob- 

 jects in view. Classification into anthracite, semi- 

 anthracite, semi-bituminous, bituminous, etc., is 

 very easy, as each of these falls in a certain area 

 of the diagram. The effects of oxidizing coals, 

 heating them, fractionating them mechanically, 

 chemically and physically, etc., are studied with 

 the revelation of many interesting relations. 

 Methods are given of judging with fair accuracy 

 the calorific value, volatile and moisture of the 

 coals in different parts of the diagram. All the 

 analyses in Bull. 22 of the Bureau of Mines are 

 plotted and constitute an interesting criticism on 

 the accuracy of work done there and seem to fall 

 within probable error, as near as such an error can 

 be calculated on such a complex substance as coal. 

 This paper will be published by the Bureau of 

 Mines. 



Osage Orange, Its Value as a Commercial Dyestuff : 



F. W. Kressmann. 



It has long been known in the southwest that 

 the wood of the Osage orange tree contains a dye- 

 stuff that would give a more or less fast yellow 

 color. 



An examination of the wood from Texas showed 

 that it not only contains moric acid and morintan- 

 nie acid, the same as fustic wood, but also that the 

 dyeing principles are present in amount to be 

 commercially valuable. A comparative series of 

 dyeing experiments made with fustic and Osage 

 orange wood and extracts showed the latter to be 

 of equal value with fustic in regard to depth of 

 colors produced, the amount of extract, the char- 

 acter of the dyeing and fastness to light, weather, 

 washing, etc. 



Some Preliminary Experiments on the Hydrolysis 

 of White Spruce, etc.: F. W. Kressmann. 

 On hydrolyzing spruce with dilute sulphuric 

 acid solutions it was found that the yields of 

 sugar increased rapidly with increasing pressures 

 of digestion up to a pressure of 7* atmospheres, 

 above which point the decrease was quite rapid. 

 The reaction is probably reversible, since the large 

 decrease can not be accounted for entirely by 

 sugar decomposition. 



About 70 per cent, of the total sugar produced 



