
          Institution? I see very little of Dr. Henry- have met
 him once or twice, but do not think we have advanced
 in acquiantance. Major Baird & Girard I also have
 gotten to know, but as I do not know any thing about
 Natural History & they do not talk chemically, our
 conversation is limited to generalities.


 I see that Regnault has been lately formalizing 
 the Boiling of water for determination of heights
 and I have been calculating with his formula & it
 gives results equal to the Barometer, the variation not
 being more than 6 feet per thousand. The modified
 formula is h = 517 T + T�, h being the 
 height, T the lowering of the Boiling in degrees reckoning
 from 212� downwards. This formula holds good
 for 10,000 feet altitude. Since this is so correct w'd [would]
 it not be well to recommend it as an additional & [?]
 means of determining heights on these expeditions when
 Barometers get broken so frequently. We carried out seven
 Bs [barometers] & brought home one safe- a portable thermom [thermometer]  c. apparatus
 might be made for the purpose? Captain Sitgreaves carried 
 out something of the kind but it was broken. What do
 you think of it.
 I have been reading Laurent's Methode de Chimie
 & think if I were teaching again I should be very
 apt to introduce his "Even numbers" & his [?]
 & "Dyads" to a class. They have many advantages over
 Electro Chemical formulae, but what could one 
 do with his double atoms, thus H�Cl� H�O
        