A minor technical change

I have altered the settings for comments very slightly. Now when you open the window to comment on a post, a box will appear asking you to copy some letters that appear as a distorted graphic. This should not be a very big burden for anybody, and I want you to know that your comments are certainly welcome. I did this not because of people who write to disagree -- anybody is welcome to disagree (though comments that contribute nothing may well be deleted, standard rules of discourse apply). The reason I did this was that I hoped to control the automatically generated comments which appear from time to time directing readers to some advertising site or another. These are, it seems, the blog equivalent of spam mail. What the comment box does is assure that there is really a living human being at the keyboard. I know that it is a bit of a silly burden, but I hope it will not discourage anybody.