From: The Science and practice of medicine, Volume 2, by William Aitken, 1866, page 553.  “Mr. A. Gardiner Brown’s spiroscope  is a new and efficient instrument for ascertaining the breathing capacity.  It is a wet meter, 6-1/2 inches square, having a dial with two registers, revolving from left to right, marking in a complete revolution 100 and 1000 cubic inches respectively, and a few feet of vulcanized India-rubber tubing to breathe through.  Its advantages are facility of management, compactness, portability, security of contained fluid and it may be used several times by the same person without readjustment. The air is measured at its initial temperature.  The patient should be taught to practice a powerful inhalation, and as complete an expiration as possible, before noting the mean numbers registered in several trials.  It should be placed at a convenient height for a person sitting or standing.”