Surveying and Levelling Instruments, Theoretically and Practically Described. For construction, qualities, selection, preservation, adjustments, and uses; with other apparatus and appliances used by civil engineers and surveyors in the field.

CHAPTER XVII.

Chapter 1713 wordsPublic domain

STATIONS OF OBSERVATION:--Pickets--False Picket--Permanent Stations--Referring Object--Heliotrope--Heliostat--Heliograph Signalling--Morse Alphabet--Night Lights--Oil Lanterns--Magnesium Light 533