Hence, to obtain great sensibility along with a considerable range, we require very long slender stems, and to these two objections apply in addition to the question of portability; for, in the first place, an instrument with a very long stem requires a very deep vessel of liquid for its complete immersion, and, in the second place, when most of the stem is above xIv.
Portability is another important issue when making a purchase.
This instrument was made with a pendulum weight of I loo kilos or over a ton; and with a modified construction the weight was increased to 17,000 kilos or nearly 19 tons, portability being obtained by replacing the solid pendulum of the smaller instrument by a shell which can be filled with barytes, a heavy mineral readily obtainable in most places.
Three modes of operation and storage, optimum portability, and image storage are critical requirements for the professional photographer.
The advantages of portability, very considerable range (from H =I upwards), and fair accuracy are claimed for the instrument.
