Skip to main content
Scientific American
  • Sign In
  • |Newsletters
  • COVID
  • Health
  • Mind & Brain
  • Environment
  • Technology
  • Space & Physics
  • Video
  • Podcasts
  • Opinion
  • Subscribe
  • Current Issue
  • Sign In
  • Newsletters
      • Share
      • Latest

      Support our Mission!

      The Sciences

      Method of Determining the Relations of the Actinism of Different Lights to the same Illuminating Power

      • October 15, 1881
      • Share on Facebook
      • Share on Twitter
      • Share on Reddit
      • Share on LinkedIn
      • Share via Email
      • Print
      Advertisement
      Advertisement

      Newsletter

      Get smart. Sign up for our email newsletter.

      Sign Up

      Support Science Journalism

      Discover world-changing science. Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners.

      Subscribe Now!Support Science Journalism

      Follow us

      • instagram
      • soundcloud
      • youtube
      • twitter
      • facebook
      • rss

      Scientific american arabic

      العربية
      • Return & Refund Policy
      • About
      • Press Room
      • FAQs
      • Contact Us
      • Site Map
      • Advertise
      • SA Custom Media
      • Terms of Use
      • Privacy Policy
      • Your US State Privacy Rights
      • Your Privacy Choices/Manage Cookies
      • International Editions
      Scientific American is part of Springer Nature, which owns or has commercial relations with thousands of scientific publications (many of them can be found at www.springernature.com/us). Scientific American maintains a strict policy of editorial independence in reporting developments in science to our readers.

      © 2023 Scientific American, a Division of Springer Nature America, Inc.

      All Rights Reserved.

      Scroll To Top

      Support science journalism.

      Scientific American paper issue and on tablet

      Thanks for reading Scientific American. Knowledge awaits.

      Already a subscriber? Sign in.

      Thanks for reading Scientific American. Create your free account or Sign in to continue.

      Create Account

      See Subscription Options

      Continue reading with a Scientific American subscription.

      You may cancel at any time.

      Sign in.