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BELL, Alexander Graham (1847-1922). Autograph letter signed ("Alexander Graham Bell") to Dr. Jay Jeffries of Boston; Washington, D.C., 3 January 1883. 1 full page, 8vo. Fine.
BELL, Alexander Graham (1847-1922). Autograph letter signed ("Alexander Graham Bell") to Dr. Jay Jeffries of Boston; Washington, D.C., 3 January 1883. 1 full page, 8vo. Fine.

细节
BELL, Alexander Graham (1847-1922). Autograph letter signed ("Alexander Graham Bell") to Dr. Jay Jeffries of Boston; Washington, D.C., 3 January 1883. 1 full page, 8vo. Fine.

EXPERIMENTS WITH BELL'S "EYE EXPLORER". Bell reports on certain recent experiments undertaken with an apparatus he has constructed to locate minute foreign particles in the eye: "I commenced the construction of an 'Eye Explorer' to be sent to you for trial. The Christmas Holidays have somewhat interfered with experimental work, so I simply write now to acknowledge receipt of your note & to let you know that I am making experiments in the direction proposed. My experiments show that almost microscopical fragments of iron can be readily detected [with his instrument], but I am more doubtful in regard to brass. Very small particles of brass produced a sensible effect, but I fear that an oculist would call my 'small' particles 'very large' indeed...."

The device may be related to the induction balance, a tool for locating metal objects in the body, with which Bell unsuccessfully attempted to locate the assassin's bullet in President Garfield.