That scheme was happily defeated, and the only modern touches added to the dale have been the galvanised wire railings recently erected along the sky-line, and the blue indicators set up on the Black Sail and Scarf Gap track.
"Climbing in The British Isles. Vol. 1 - England"
W. P. Haskett Smith
Red Blood Corpuscles as indicators of Isotony.
"The Mechanism of Life"
Stéphane Leduc
indicators gave readings, quite a few hundred readings.
"Evil Out of Onzar"
Mark Ganes