> According to the gemara, eg BK 50b-51a, a bor that is 10 tefachim deep<br>> or more contains hevel which is dangerous to breathe. And even if it's<br>> less than 10 tefachim, the air is still injurious.<br>> My father was surprised that he couldn't find any rishonim or acharonim
<br>> who compare this to the experimental data. Not whether to dismiss it or<br>> explain how it works -- no one seems to think it's intriguing and worth<br>> discussion?!<br><br>Why is this more problematical then myriads of other gemarot that dont compare to
<br>experimental data. An example from recent daf yomi (Yevamot 120).<br>Chachamim don't rely on "shuma" for personal identification while<br>R. Elazar ben Mehavai does<br>1. argument is whether most people born in the same "Mazal" have similar "shuma"
<br>2. argument is whether "shuma" changes after death<br><br>either explanation sounds like it could be easily checked by experiment, ie are they<br>arguing about facts?<br clear="all"><br>-- <br>Eli Turkel