Thus the whole method of measurement in geometry as described in the elementary textbooks and the older treatises is obscure to the last degree.
Complex spectra of stars of the solar type this is by no means the case; for, as Dr Hartmann remarks, " in the first place the lines in these spectra are so numerous that their complete measurement and reduction would require many days, and in the second place a rigorous reduction of such material has hitherto not been at all possible because the wave-lengths of the lines are not known with sufficient accuracy.
The celebrated Newland oak in Gloucestershire, known for centuries as "the great oak," was by the latest measurement 472 ft.
AMPEREMETER, or Ammeter, an instrument for the measurement of electric currents in terms of the unit called the ampere.
The above-described gravity type can be employed with certain restrictions for the measurement of alternating currents.