148 
Economy of Nitrogen. 
[April, 
whole of Europe at about 540,000 lbs,, requiring the con- 
sumption of about 6^- millions lbs. of bones, which would 
otherwise be available as manure. If we assume that the 
skeleton of an average man, when dry, weighs 20 lbs., this 
weight would furnish the bony framework for the bodies of 
325,000 human beings. As each match is struck, its pro- 
portion of phosphorus is converted into phosphoric acid. 
Such conversion does not necessarily imply waste, since this 
is precisely the form in which phosphorus enters into the 
food of plants. But the phosphoric acid is scattered abroad 
in such minute portions that we may well question whether 
much of it will, in any reasonable time, find its way to its 
legitimate place, our fields and gardens. If we duly weigh 
how much nutritive matter is thus in effeCt destroyed, and 
how much potential life is prevented, we may well question 
whether the invention of “ lucifers ” has been quite as great 
a boon to mankind as is sometimes represented by platform- 
orators, and whether the power of instantaneously obtaining 
a light at all times and in all places is not being, to say the 
least, somewhat dearly purchased. It is perfectly possible 
to make matches without the consumption of any phosphorus 
at all — a faCt too much lost sight of and too little aCted 
upon, but which will ultimately force itself upon the public 
attention. 
Bone-black or animal charcoal is largely used for water- 
filters, in sugar-refining, in the manufacture of blacking, 
and as a pigment, and contains about 70 per cent of phos- 
phate of lime. That portion applied for filtering and for 
sugar-refining finds its way in course of time to the manure 
manufacturer, and ultimately to the soil. The amount used 
for blacking and for pigments is evidently squandered about 
in traces far too minute to be again collected by any human 
agency. To protest against so long-established and general 
a custom as giving a black surface to coverings for the feet 
is of course a hopeless task ; yet if we consider that any 
material coloured black radiates heat more strongly than the 
same material coated with any other colour, we must admit 
the folly both of blacking, as applied to boots and shoes, 
and of the original blackening of shoe-leather before it 
leaves the hands of the currier. Our universal practice can 
only be considered rational if we wish to have our feet as 
hot as possible in summer and as cold as possible in winter. 
Bone-ashes consist, of course, chiefly of the phosphate of 
lime, and are mainly utilised in agriculture. But a small 
portion is used in making cupells for the assayer, and in the 
manufacture of opal glass. The phosphorus that enters 
