Read Capacity for Murder (Professor Bradshaw Mysteries) for Free Online Page A

shook back his cuff to expose his wrist, and applied the end to his skin. He felt a pricking heat, and smelled the sharpness of ozone. He glanced at Hornsby and saw him shaking his head, his eyes wide.
    “I understand you weren’t using diathermy on David, I’m simply checking the output.”
    “It’s not that, Professor. It’s the sound. The sound is different. It was different.”
    “The sound emitted by the spark interrupter you mean? How so?”
    “Now it sounds as it usually does. Crackling, and with that small bright arc. But with David that morning, it was different, more like a hiss. And the arc flamed.”
    Hornsby’s confused expression showed his lack of understanding, but Bradshaw’s chest tightened. He knew what that change in sound indicated. He unplugged the machine, discharged the Leyden jars, then examined the interior closely. Using a magnifying glass he examined the insulating space between the primary and secondary coils, then he went over every inch of the Leyden jars, spotting two inconclusive darkish smudges on the outer foil and the connecting posts of the caps.
    He straightened, leaving the machine open.
    “Doctor, would you step into your office, please? Leave the door ajar. Have a seat, and when I tell you to, please listen carefully.”
    Hornsby did as asked without question, for which Bradshaw was grateful. He was about to attempt to replicate what had happened to David Hollister and it was unnecessary for Hornsby to put himself through it. It would be enough that from the adjoining room he would be able to hear the sound of the spark gap.
    Deputy Mitchell rubbed his chin, looking uncomfortable. “Where do you want me, Professor?”
    “In the doorway is fine if you want to observe.”
    The deputy took up a position in the door where he could see both Bradshaw and Hornsby.
    From his electric kit, Bradshaw found a length of copper wire, and he stood for a moment considering it. He glanced around the room at Hornsby’s electrotherapeutic supplies, searching for something of the right size and conductivity. The electrodes and knives all possessed insulated handles. A small spool of copper or a roll of sheet block tin would suit his need, and many physicians who worked on their own machines and fashioned their own instruments possessed them. He stepped to the doorway and asked Hornsby about them.
    Hornsby shook his head. “I don’t keep wire or tin in here. David has those in the washhouse. If I ever needed anything, I’d simply ask him.”
    “I see. Thank you.”
    He returned to the open cabinet of the outfit and positioned the copper wire across the Leyden jars in a manner that shorted the path of the current passing through them. With a glance to the doorway to see that the deputy wasn’t paying attention, he pulled the patty pan squash from his pocket, and inserted a small electrode into the flesh to ensure a current path. He turned the machine’s dials to the autocondensation settings, soaked the felt pad in salt water and placed it over the squash on the therapy chair, which he also attached to the machine. His last step was to wire an ammeter into the circuit to measure the current. When all was in readiness, he screwed the plug into the light socket and threw the knife switch. The spark gap produced a glowing, hissing flame, distinctly different from the earlier crackling spark. He heard a gasp from the other room. The ammeter registered a lethal amperage. The felt pad steamed.
    David Hollister would have been dead almost instantly. With a small tremor, and perhaps a silent gasp. Or an attempt to gasp. His heart would have stopped, irrevocably damaged.
    Bradshaw cut the knife switch and slipped the warm patty pan into his pocket before asking Dr. Hornsby to return. The deputy stepped aside to allow Hornsby, pale and trembling, to enter.
    Bradshaw asked, “Did you recognize the sound?”
    “Yes, that was it exactly. What did you do?”
    In short-circuiting the capacitor, he’d