FIG. 14. DIAGRAM SHOWING TENSION IN CROOKES’ APPARATUS UNDER HOME’S INFLUENCE.
“Experiment IV.—(Tried on an occasion when the power was stronger than on the previous occasions), Mr. Home was now placed 3 feet from the apparatus, his hands and feet being tightly held. The clock was set going when he gave the word, and the end, B, of the board soon descended, and again rose in an irregular manner, as shown in Fig. 15.
SCALE THE SAME AS IN FIG. 12.
FIG. 15. DIAGRAM SHOWING TENSION IN CROOKES’ APPARATUS UNDER HOME’S INFLUENCE.
“The following series of experiments were tried with more delicate apparatus, and with another person, a lady, Mr. Home being absent. As the lady is non-professional, I do not mention her name. She has, however, consented to meet any scientific men whom I may introduce for purposes of investigation.
FIG. 16. SECOND CROOKES’ APPARATUS.
“A piece of thin parchment, A, (Figs. 16 and 17), is stretched tightly across a circular hoop of wood. B C is a light lever turning on D. At the end B is a vertical needle point touching the membrane A, and at C is another needle point, projecting horizontally and touching a smoked glass plate, E F. This glass plate is drawn along in the direction H G by clockwork, K. The end, B, of the lever is weighted so that it shall quickly follow the movements of the centre of the disc, A. These movements are transmitted and recorded on the glass plate, E F, by means of the lever and needle point, C. Holes are cut in the side of the hoop to allow a free passage of air to the under side of the membrane. The apparatus was well tested beforehand by myself and others, to see that no shaking or jar on the table or support would interfere with the results: the line traced by the point, C, on the smoked glass was perfectly straight in spite of all our attempts to influence the lever by shaking the stand or stamping on the floor.
