TRANSCRIBER’S NOTE
Reading edition
Fractions are represented horizontally using the slash / symbol. The original separated the numerator and denominator horizontally, separated by a _ line.
Punctuation has been normalized. Except in the following cases, variations in hyphenation, spelling and spacing have been retained as they were in the original publication.
Chapter 2:
Lumer-Brodhum photometer —> Lummer-Brodhun photometer
Chapter 4:
What appear to be hand-drawn primes in the text have been confirmed as: The arc ha´ce —> The arc ha´c´e´.
e c a a´ c e´ —> e c a a´ c´ e´
Figure IV
There are two points b radiating from point O. The lower is likely to represent b´.
Chapter 5:
inportant difference between —> important difference between