thanks, i see... i read about travels to Egypt, and then curiosity on heat transport. back in that time, heat was understood differently than today, but interesting to see how the fluctuations in temperature of day/night of month/year follow a bit of sinusoidal pattern indeed. do you recall what those basic heat equations were back in that time, and why it was different from theories back then? just in case you have some more time to write on this.... thanks!