“Because the occupant of that place has made a discovery for which scientists have for years striven in vain,” the doctor replied.
“What is it?”
“You noticed those strange globes with the coil of tubing,” he said. “Well, from what I’ve found, it seems that the experimenter has invented a means for the liquefaction of hydrogen in large quantities.”
“Is that anything very remarkable?” I asked, in my ignorance of recent science.
“Remarkable!” he echoed. “I should rather say it was. The discovery will create the greatest interest in the scientific world. Other gases have all been handled as true liquids in measurable quantities, while until now hydrogen has only been seen in clouds or droplets, and never collected into a liquid mass. Upstairs, however, there is actually a glass bowl of liquid hydrogen. The experimenter, whoever he is, has determined at last the exact temperature at which it will liquefy, and thus a field for quite new researches, as also for new generalisations, has been thrown wide open.”
“But why is the discovery so very important?” I asked, still puzzled at the doctor’s unusual enthusiasm.
“Briefly, because by it physicists and chemists can henceforward obtain temperatures lying within thirty-five degrees from the so-called absolute zero of temperature—minus 459 degrees Fahrenheit. A possibility is thus given to study physical bodies in the vicinity of that point, which represents, so to say, the death of matter—that is, absence of the molecular vibrations which we describe as heat.”
This explanation, technical though it was, interested me. I knew Doctor Lees Knowles to be a rising man, and when reporting lectures at the Royal Institution had often noticed him among the audiences. There was no doubt that he was highly excited over the discovery, for, like myself, he had seen the liquid hydrogen boiling without any visible heat. In the papers there had been lots about Professor Dewar’s experiments in the liquefaction of oxygen, fluorine and the newly-discovered helium, and I remembered how all his efforts to bring hydrogen to a liquid state had failed. Now, however, the mysterious occupier of that house had succeeded, and every known gas could now be liquefied.
“But the murder,” observed Patterson, his thoughts reverting to the crime, for to him the most wonderful scientific discovery was as naught. “Can you form absolutely no opinion as to how it was accomplished?”
The doctor shook his head.