How to handle 404 not found errors in Nokogiri

I am using Nokogiri to scrape web pages. Few urls need to be guessed and returns 404 not found error when they don't exist. Is there a way to capture this exception? http://yoursite/page/38475 #=> page number 38475 doesn't exist I tried the following which didn't work. url = "http://yoursite/page/38475" doc = Nokogiri::HTML(open(url)) do begin rescue Exception => e puts "Try again later" end end