SCIENCE. 



455 



by heating to 68°, then polarizing again, carefully noting 

 the temperature. From these readings the percentage of 

 cane sugar present is calculated from the following for- 

 mula : 



a — a' 



144 — 



Here a=first reading of polariscope. 

 a'=second reading of polariscope. 

 t=temperature of observation. 

 x=percentage cane sugar required. 

 In connection with the polariscope readings I also 

 made reductions both before and after inversion, and 

 thus obtained valuable data in regard to the nature of 

 the amylose present, as well as securing a check on the 

 optical results. 



Following is a scheme of an analysis which will illu- 

 strate the method of procedure : 



Reduction. Took log. in 1000 c.c. Of this, to reduce 

 ioc.c. Fehling's Solution, took 27.8 c.c. 



Then 1000: 27.S = x : .05 (.05 g = sugar corresponding 

 to 10 c.c. copper solution.) 



Whence x = 1.8 g. - 18 percent reducing matter. 



Polarization. 26.048 g. in 100 c.c. gave 97°-8+ 



After inversion at 21 " 2°. 6 — 



Difference, = ioo°.4 



21 



ioo p .4-h 144 — 75.2 = per cent sucrose. 



Reduction after inversion. 



For ioc.c. copper solution took 5.35 c.c. 

 Then 1000 : 5.35 = x : .05. 



x = 9.35 g. = 93. 50 per cent. 



Deduct 18 per cent due to amylose = . . 75. 50 " 



Due to invert sugar 



Sucrose by polariscope 75 2 " 



Amylose, water and ash by difference. . . 24 8 " 



Following are the results of twelve examinations of 

 mixed sugar : 



Per cent Per cent Amylose, Water, 



No. Reducing Sucrose by Ash, etc., 



Matter. Polariscope. by difference. 



1 *2970 *7 1 .4 28.6 



2 24.6 64.35 35- 6 5 



3 25.64 68.2 31.80 



4 25.00 64.72 35—8 



5 22.52 66.80 33.20 



6 24.4 60.34 39.66 



7 26.88 60.7 39 3° 



8 25.00 68.6 31 .40 



9 3°-S 59-9 4°. 10 



10 25.8 71.6 28.40 



11 26.6 61.0 39 00 



12 18.0 75.4 24.60 



The analysis of mixed sugars is at this time a matter 

 of great public interest. It is important that the public 

 be not defrauded by purchasing sugars under false names. 

 It is true that the manufacturers, as far as I know, do 

 not sell the mixed sugars as straight, but when they 

 pass into the hands of the retail dealers they are usu- 

 ally disposed of as if they were genuine. I do not antici- 

 pate that mixed sugars will jeopardize the public health. 

 When well made they are certainly palatable and harm- 

 less. For boiling with fruits, etc., as in making pre- 

 serves, they are quite as efficient as cane sugars. Never- 

 theless a " mixed sugar " should be bought, sold, and 

 consumed as a mixed sugar, and thus all " winking " at 

 fraud be prevented. 



* One of these numbers is evidently incorrect. On looking over my notes 

 I cannot find the mistake, and I have no more of the sugar with which to 

 repeat the analysis. I think the error is in the per cent of reducing mat- 

 ter. — H. W. W. 



COAL DUST AS AN ELEMENT OF DANGER 

 IN MINING; SHOWN BY THE LATE EX- 

 PLOSION IN THE ALBION MINES IN NOVA 

 SCOTIA* 



By H. C. Hove y. 



My object, in this communication, is to lay before the 

 public by permission of Mr. Edward Gilpin, Inspector of 

 Mines for Nova Scotia, the results of his investigations 

 into the part played by coal dust in spreading and aug- 

 menting the terrible explosion that took place in the 

 Albion mines, near Stellarton, on the East river, N. S., 

 on the 1 2th of November, 1880. 



Explosions are frequent in the coal mines of England 

 and Belgium, causing loss of many lives and the 

 destruction of much property. But in our own country, 

 as a rule, we are fortunately exempt from such calamities. 

 On the other side of the Atlantic there are special causes 

 leading to these explosions ; the thinness of the seams, 

 the depth of the workings, the gaseous nature of the 

 coals most prized for their coke and illuminating power, 

 all combining to render difficult the great problem of 

 producing ventilating currents sufficiently powerful and 

 searching to insure the safety of the workmen. 



Within the last few years men of scientific and practical 

 knowledge have studied into these disasters and their 

 causes, hoping that some remedy might be found that 

 could remove the dreadful uncertainty hanging over the 

 lives of those who help to sustain the fabric of modern 

 civilisation. It was discovered by a rigid inspection of 

 all available accounts of explosions, that many of them 

 had occurred in pits known to be, as a rule, not danger- 

 ous from explosive gas, or declared to be free from it 

 shortly before the moment of the accident. Then the 

 fact gradually became apparent that a seemingly inno- 

 cuous constituent of the mines, namely, coal dust, played 

 an important part in spreading and augmenting the 

 blasts. It was as if the wadding of a gun was composed 

 of an inflammable material which, on ignition of the 

 charge, doubled its effect. 



It is well-known that chemical action is often induced 

 in heaps of slack, such as exist in thick coal workings, 

 and that the heat evolved may be enough to cause igni- 

 tion. The danger is increased when the broken coal is 

 comminuted, and floats in the air, as in this form, under 

 various conditions, it may undergo rapid oxidation. 

 Galloway's experiments show that when the particles of 

 dust are so fine as to pass through the gauze shield of a 

 safety lamp, an explosion may be caused by their igni- 

 tion. Bauerman states that, in the Franco-Belgian col- 

 lieries, " several fatal explosions have been traced to the 

 firing of coal dust from the flame of a shot, even in cases 

 where no fire-damp was present in the workings." 



A brief glance at the history of the Albion Mines will 

 not be misplaced. The main seam, which has been con- 

 tinuously worked since 1807, attains the remarkable thick- 

 ness of 37 feet 6 inches, and is a highly bituminous coal, 

 well adapted for gas and coke-making. It contains sev- 

 eral layers of iron stone up to one foot in thickness, but 

 may be considered as an unbroken mass of coal. 



The earliest workings, now known as " the Burnt 

 Mines," furnished large quantities of coal, until they 

 were abandoned in 1839 on account of fire, which blazed 

 so fiercely from the shafts that the chains used in raising 

 the coal tubs, were melted. A new opening, the Bye 

 Pit, was worked till 1863, when a fire occurred from a 

 shot lighting gas. This was extinguished ; but a short 

 time after the gas ignited at the boilers, which were 

 within a few yards ot the top of the pit. and the works 

 had to be closed up. The Foster Pit was next opened, 

 but in 1869 spontaneous combustion caused a fire, which 

 necessitated its abandonment before it was fairly under 

 way. 



* Read before the A. A. A..S., Cincinnati, 1881. 



