EFFECTS OF CONSTITUENTS OF ASH. 17 



sample of tobacco with good burning qualities is saturated with a 

 10 per cent solution of the nitrate and dried, it burns with extreme 

 rapidity, almost explosively, and gives a remarkably white ash, while 

 with samples of tobacco with poor burning qualities scarcely any 

 beneficial effects are produced. More dilute solutions, such as were 

 used in the case of the other salts, do not produce any appreciable 

 effects. Moreover, it requires a concentrated solution to impart to 

 filter paper a good fire-holding capacity. It seems likely that the 

 effects of the concentrated solution on the tobacco with the good 

 burning qualities are due largely to reaction of the calcium nitrate 

 with potash salts in the leaf. So far as could be determined no 

 marked effects are produced by adding calcium phosphate to tobacco. 

 The acetate of calcium is of special interest because it is readily sol- 

 uble and thus furnishes an opportunity of comparing the relative 

 effects of potassium, calcium, and magnesium on the burning quali- 

 ties. Of a large number of samples of tobacco tested a few were im- 

 proved by the acetate, but the greater number were scarcely affected 

 as regards the capacity for holding fire. In every case, however, the 

 color of the ash was very materially improved. None of the remain- 

 ing salts of calcium to be considered are easily soluble, but so far as 

 could be determined they neither injure nor improve the fire-holding 

 capacity to any considerable extent, but all give a decidedly whiter 

 ash. 



MAGNESIUM. 



All the salts of magnesium are readily soluble except the phos- 

 phates, and so it is much easier to get satisfactory results with them 

 than is the case with the calcium compounds. The chlorid and sul- 

 phate are both very decidedly injurious to the burn, and the addition 

 of even small quantities will destroy the glowing capacity of tobacco 

 having the very best burning qualities. The sulphate is much more 

 injurious than the corresponding calcium salt. The nitrate acts very 

 much like the calcium compound, but its action when applied in con- 

 centrated solution is less marked. When applied to filter paper it 

 shows the peculiar property of charring the paper in wave-like forms 

 much in advance of the burning portion. The phosphate of mag- 

 nesium appears to be more injurious to the burn than the correspond- 

 ing calcium compound. The acetate was found to injure the burning 

 qualities in every case, but to a lesser extent than the inorganic salts. 

 The citrate, malate, and oxalate in a few. cases did not interfere with 

 the burn, but in the greater number harmful effects were observed. 

 All of the salts of magnesium, like those of calcium, tend to produce 

 a white ash. 



105 



wr 'nuifi 



