$20.00 – $85.00
Ophthalmoscope (for examining eyes)
2 patents – 1 one for a new and improved version, 1 for a battery dry handle.
First USA patent on the stethoscope – for a concealed noiseless spring that eliminated vibrations.
Bausch and Lomb Microscope
First Bausch & Lomb microscope. Both witnessed the patent document. Print includes these signatures.
Mortar and Pestle
Blood Pressure Manometer
2 patents – construction improvement for less breakage and better accuracy, second has a mercury reservoir and glass measuring tube.
Felix Hoffman's patent on his refinement of the formulation that Charles Frederic Gerhardt tried but gave up on.
Phoropter (for eye testing)
Invented by Henry DeZeng, who also trademarked the word Phoropter – a word that is now used for visual testers.
2 patents – 1 for the design of chair, 1 for the cup holder for spittoon.