He tried jets of steam and of air with sand, and found that he could roughen a pane of glass almost instantly.  By coating a part of the glass with hot beeswax, applied with a brush, through a stencil, or covering it with paper cut into any desired figures, he could engrave the most delicate and intricate patterns as readily as if plain.  Glass is often made all white, except a very thin coating of brilliant colored glass on one side.  This he could cut through, leaving letters of brilliant color and the general surface white, or vice versa.

Seal cutting is a very delicate and difficult art, old as the Pharaohs.  Protect the surface that is to be left, and the sand blast will cut out the required design neatly and swiftly.

There is no known substance, not even corundum, hard enough to resist the swift impact of myriads of little stones.

It will cut more granite into shape in an hour than a man can in a day.

Surely no one will be sorry to learn that General Tilghman sold part of his patents, taken out in October, 1870, for $400,000, and receives the untold benefits of the rest to this day.  So much for thinking.

Nature gives thousands of hints.  Some can take them; some can only take the other thing.  The hints are greatly preferred by nature and man.

CREATIONS NOW IN PROGRESS

The forces of creation are yet in full play.  Who can direct them?  Rewards greater than Tilghman’s await the thinker.  We are permitted not only to think God’s thoughts after him, but to do his works.  “Greater works than these that I do shall he do who believeth on me,” says the Greatest Worker.  Great profit incites to do the work noted below.

Carbon as charcoal is worth about six cents a bushel; as plumbago, for lead pencils or for the bicycle chain, it is worth more; as diamond it has been sold for $500,000 for less than an ounce, and that was regarded as less than half its value.  Such a stone is so valuable that $15,000 has been spent in grinding and polishing its surface.  The glazier pays $5.00 for a bit of carbon so small that it would take about ten thousand of them to make an ounce.

Why is there such a difference in value?  Simply arrangement and compactness.  Can we so enormously enhance the value of a bushel of charcoal by arrangement and compression?  Not very satisfactorily as yet.  We can apply almost limitless pressure, but that does not make diamonds.  Every particle must go to its place by some law and force we have not yet attained the mastery of.

We do not know and control the law and force in nature that would enable us to say to a few million bricks, stones, bits of glass, etc., “Fly up through earth, water, and air, and combine into a perfect palace, with walls, buttresses, towers, and windows all in exact architectural harmony.”  But there is such a law and force for crystals, if not for palaces.  There is wisdom to originate and power to manage such a force.  It does not take masses of rock and stick them together, nor even particles from a fluid, but atoms from a gas.  Atoms as fine as those of air must be taken and put in their place, one by one, under enormous pressure, to have the resulting crystal as compact as a diamond.