1850—1854 65 



prepared to follow most minutely the indications that I shall 

 give him in order to obtain this singular substance in quantities 

 such that it can again be easily turned into commercial use. 

 I can already conceive the history of this product. M. Kestner 

 must have had at his disposal in 1820 some Neapolitan tartars, 

 as indeed he said he had, and he must have operated on crude 

 tartar. That is the whole secret. . . . But is it certain that 

 almost the whole of the acid is lost in the first manufacture 

 undergone by tartar? I believe it is. But it must be proved. 

 There are at Trieste and at Venice two tartar refineries of 

 which I have the addresses. I also have letters of introduction. 

 I shall examine there (if I find a laboratory) the residual pro- 

 ducts, and I shall make minute inquiries respecting the places 

 the tartars used in those two cities come from. Finally, I shall 

 procure a few kilogrammes, which I shall carefully study when 

 I get back to France. ..." 



Freiberg, September 23, 1852. " I arrived on the evening 

 of the 21st at Dresden, and I had to wait until eleven the next 

 morning to have my passport vise, so I could not start for 

 Freiberg before seven p.m. I took advantage of that day to 

 visit the capital of Saxony, and I can assure you that I saw 

 some admirable things. There is a most beautiful museum 

 containing pictures by the first masters of every school. I 

 spent over four hours in the galleries, noting on my catalogue 

 the pictures I most enjoyed. Those I liked I marked with a 

 cross; but I soon put two, three crosses, according to the 

 degree of my enthusiasm. I even went as far as four. 



"I also visited what they call the green vault room, an 

 absolutely unique collection of works of art, gems, jewels . . . 

 then some churches, avenues, admirable bridges across the 

 Elbe. . . . 



" I then started for Freiberg at 7. . . . My love of crystals 

 took me first to the learned Professor of mineralogy, Breithaupt, 

 who received me as one would not be received in France. 

 After a short colloquy, he passed into the next room, came back 

 in a black tail-coat with three little decorations in his button 

 hole, and told me he would first present me to the Baron von 

 Beust, Superintendent of Factories, so as to obtain a permit 

 to visit the latter. . . . Then he took me for a walk, talking 

 crystals the whole time. ..." 



P.S.— " Mind you tell M. Biot how I was received; It will 



please him." 



F 



