He shifted his position slowly, and went on, as if defending the course of action he had taken in the case.

"Then, too, you know, there is an individual as well as family and s.e.x susceptibility to lead. Women are especially liable to lead poisoning, but then perhaps in this case Mrs. Pearcy comes of a family that is very resistant. There are many factors. Personally, I don't think Pearcy himself was resistant. Perhaps Minturn was not, either. At any rate, after Pearcy's death, it was I who advised Minturn to take the electrolysis cure in New York. I took him down there," added Gunther.

"Confound it, I wish I had stayed with him. But I always found Josephson perfectly reliable in hydrotherapy with other patients I sent to him, and I understood that he had been very successful with cases sent to him by many physicians in the city." He paused and I waited anxiously to see whether Kennedy would make some reference to the discovery of the strychnine salts.

"Have you any idea how the lead poisoning could have been caused?"

asked Kennedy instead.

Dr. Gunther shook his head. "It is a puzzle to me," he answered. "I am sure of only one thing. It could not be from working in lead, for it is needless to say that none of them worked."

"Food?" Craig suggested.

The doctor considered. "I had thought of that. I know that many cases of lead poisoning have been traced to the presence of the stuff in ordinary foods, drugs and drinks. I have examined the foods, especially the bread. They don't use canned goods. I even went so far as to examine the kitchen ware to see if there could be anything wrong with the glazing. They don't drink wines and beers, into which now and then the stuff seems to get."

"You seem to have a good grasp of the subject," flattered Kennedy, as we rose to go. "I can hardly blame you for neglecting the water, since everyone here seems to be so sure of the purity of the supply."

Gunther said nothing. I was not surprised, for, at the very least, no one likes to have an outsider come in and put his finger directly on the raw spot. What more there might be to it, I could only conjecture.

We left the druggist's and Kennedy, glancing at his watch, remarked: "If you will go down to the station, Walter, and get that package we left there, I shall be much obliged to you. I want to make just one more stop, at the office of the water company, and I think I shall just about have time for it. There's a pretty good restaurant across the street. Meet me there, and by that time I shall know whether to carry out a little plan I have outlined or not."

CHAPTER x.x.x

THE ELECTROLYTIC MURDER

We dined leisurely, which seemed strange to me, for it was not Kennedy's custom to let moments fly uselessly when he was on a case.

However, I soon found out why it was. He was waiting for darkness.

As soon as the lights began to glow in the little stores on the main street, we sallied forth, taking the direction of the Pearcy and Minturn houses.

On the way he dropped into the hardware store and purchased a light spade and one of the small pocket electric flashlights, about which he wrapped a piece of cardboard in such a way as to make a most effective dark lantern.

We trudged along in silence, occasionally changing from carrying the heavy package to the light spade.

Both the Pearcy and Minturn houses were in nearly total darkness when we arrived. They set well back from the road and were plentifully shielded by shrubbery. Then, too, at night it was not a much frequented neighborhood. We could easily hear the footsteps of anyone approaching on the walk, and an occasional automobile gliding past did not worry us in the least.

"I have calculated carefully from an examination of the water company's map," said Craig, "just where the water pipe of the two houses branches off from the main in the road."

After a measurement or two from some landmark, we set to work a few feet inside, under cover of the bushes and the shadows, like two grave diggers.

Kennedy had been wielding the spade vigorously for a few minutes when it touched something metallic. There, just beneath the frost line, we came upon the service pipe.

He widened the hole, and carefully sc.r.a.ped off the damp earth that adhered to the pipe. Next he found a valve where he shut off the water and cut out a small piece of the pipe.

"I hope they don't suspect anything like this in the houses with their water cut off," he remarked as he carefully split the piece open lengthwise and examined it under the light.

On the interior of the pipe could be seen patchy lumps of white which projected about an eighth of an inch above the internal surface. As the pipe dried in the warm night air, they could easily be brushed off as a white powder.

"What is it--strychnine?" I asked.

"No," he replied, regarding it thoughtfully with some satisfaction.

"That is lead carbonate. There can be no doubt that the turbidity of the water was due to this powder in suspension. A little dissolves in the water, while the scales and incrustations in fine particles are carried along in the current. As a matter of fact the amount necessary to make the water poisonous need not be large."

He applied a little instrument to the cut ends of the pipe. As I bent over, I could see the needle on its dial deflected just a bit.

"My voltmeter," he said, reading it, "shows that there is a current of about 1.8 volts pa.s.sing through this pipe all the time."

"Electrolysis of water pipes!" I exclaimed, thinking of statements I had heard by engineers. "That's what they mean by stray or vagabond currents, isn't it?"

He had seized the lantern and was eagerly following up and down the line of the water pipe. At last he stopped, with a low exclamation, at a point where an electric light wire supplying the Minturn cottage crossed overhead. Fastened inconspicuously to the trunk of a tree which served as a support for the wire was another wire which led down from it and was buried in the ground.

Craig turned up the soft earth as fast as he could, until he reached the pipe at this point. There was the buried wire wound several times around it.

As quickly and as neatly as he could he inserted a connection between the severed ends of the pipe to restore the flow of water to the houses, turned on the water and covered up the holes he had dug. Then he unwrapped the package which we had tugged about all day, and in a narrow path between the bushes which led to the point where the wire had tapped the electric light feed he placed in a shallow hole in the ground a peculiar apparatus.

As nearly as I could make it out, it consisted of two flat platforms between which, covered over and projected, was a slip of paper which moved forward, actuated by clockwork, and pressed on by a sort of stylus. Then he covered it over lightly with dirt so that, unless anyone had been looking for it, it would never be noticed.

It was late when we reached the city again, but Kennedy had one more piece of work and that devolved on me. All the way down on the train he had been writing and rewriting something.

"Walter," he said, as the train pulled into the station, "I want that published in to-morrow's papers."

I looked over what he had written. It was one of the most sensational stories I have ever fathered, beginning, "Latest of the victims of the unknown poisoner of whole families in Stratfield, Connecticut, is Miss Isabel Pearcy, whose father, Randall Pearcy, died last week."

I knew that it was a "plant" of some kind, for so far he had discovered no evidence that Miss Pearcy had been affected. What his purpose was, I could not guess, but I got the story printed.

The next morning early Kennedy was quietly at work in the laboratory.

"What is this treatment of lead poisoning by electrolysis?" I asked, now that there had come a lull when I might get an intelligible answer.

"How does it work?"

"Brand new, Walter," replied Kennedy. "It has been discovered that ions will flow directly through the membranes."

"Ions?" I repeated. "What are ions?"

"Travelers," he answered, smiling, "so named by Faraday from the Greek verb, io, to go. They are little positive and negative charges of electricity of which molecules are composed. You know some believe now that matter is really composed of electrical energy. I think I can explain it best by a simile I use with my cla.s.ses. It is as though you had a ballroom in which the dancers in couples represent the neutral molecules. There are a certain number of isolated ladies and gentlemen--dissociated ions--" "Who don't know these new dances?" I interrupted.

"They all know this dance," he laughed. "But, to be serious in the simile, suppose at one end of the room there is a large mirror and at the other a buffet with cigars and champagne. What happens to the dissociated ions?"

"Well, I suppose you want me to say that the ladies gather about the mirror and the men about the buffet."

"Exactly. And some of the dancing partners separate and follow the crowd. Well, that room presents a picture of what happens in an electrolytic solution at the moment when the electric current is pa.s.sing through it."

"Thanks," I laughed. "That was quite adequate to my immature understanding."

Kennedy continued at work, checking up and arranging his data until the middle of the afternoon, when he went up to Stratfield.