It should be mentioned that the infra-red rays have a remarkable damping effect on the phenomena of phosphorescence, a fact which has.
Pythium, which causes the damping off of seedlings, reducing them to a putrid mass in a few hours, and Phytophthora, the agent of the potato disease.
Grassot has devised a galvanometer, or " fluxmeter," which greatly alleviates the tedious operation of taking ballistic readings.2 The instrument is of the d'Arsonval type; its coil turns in a strong uniform field, and is suspended in such a manner that torsion is practically negligible, the swings of the coil being limited by damping influences, chiefly electromagnetic. The index therefore remains almost stationary at the limit of its deflection, and the deflection is approximately the same whether the change of induction occurs suddenly or gradually.
The weighing is conducted in the usual way by vibrations, except when the weight be small; it is then advisable to bring the pointer to zero, an operation rendered necessary by the damping due to the adhesion of water to the fibre.
Between loss and delay the spinner found an obvious alternative in damping the yarn artificially.