As to Keller, he was a simple German, by trade a paper-maker and by avocation a scientist of sorts.  One day in 1840—­and this marks the beginning of the accidents—­returning home from his mill, he trod upon the abandoned nest.  Had not the tiny dwelling been deserted, he probably would have cherished nothing but bitter reflections about the irascibility of wasps.  As it was, he stooped to see the ruin he had wrought.

The crushed nest lay soft in his hand, soft and pliable, and yet tough in texture.  It was as soft as his own rag-made paper.  It was not paper, and yet it was very much like paper.  Crumbling It in his fingers, he decided that its material was wood-pulp.

Keller was puzzled to know how so minute a creature had welded wood into a paperlike nest.  His state of mind passed to interest, thence to speculation, and finally to investigation.  He carried his problem and its possibilities to his friend, Heinrich Voelter, a master mechanic.  Together they began experiments.  They decided to emulate the wasp.  They would have to granulate the wood as she had done.  The insect had apparently used spruce; they used spruce under an ordinary grindstone.  Hot water served as a substitute for the wasp’s salivary juices.

Their first attempts gave them a pulp astonishingly similar to that resulting from the choicest rags.  They carried the pulp through to manufacture, with a small proportion of rags added—­and they had paper.  It was good paper, paper that had strength.  They found that it possessed an unlooked-for advantage in its quick absorption of printing-ink.

Have you followed the chain of accidents, coincidences, and fortunate circumstances?  Suppose the wasp had not left her nest in Keller’s path.  What if he had been in haste, or had been driven off by the queen’s yellow-jacketed soldiers?  What if he had no curiosity, if he had not been a paper-maker, if he had not enjoyed acquaintance with Voelter?  Wood-pulp might never have been found.

Leaving Gottfried Keller and Voelter in their hour of success, we find, sixteen years afterward, two other Germans, Albrecht and Rudolf Pagenstecher, brothers, in the export trade in New York.  They were pioneering in another field.  They were shipping petroleum to Europe for those rising young business men, John D. and William Rockefeller.  They were seeking commodities for import when their cousin, Alberto Pagenstecher, arrived from the fatherland with an interesting bit of news.

“A few weeks ago, in a paper-mill in the Hartz, I found them using a new process,” he said.  “They are making paper out of wood.  It serves.  Germany is printing its newspapers on wood-pulp paper.”

To his cousins it seemed preposterous that wood could be so converted, but Alberto was convincing.  He showed them Voelter’s patent grants and pictures of the grinders.  The Pagenstechers went to Germany, and when they returned they brought two of the grinders—­crude affairs devised for the simple purpose of pressing wood upon a stone.  They also brought with them several German mechanics.