French Letter written by the Comte De Saint Germain in 1735

These two pages are to the same letter written by 

the Comte de Saint Germain in 1735. The Original is or was (?) in the British Museum in 1912 or therabouts when I. Cooper Oakley wrote her book called  "The Comte de Saint Germain" in 1912 and included a photocopy? there. I have one of these copies printed in 1912 and obtained by my parents in the 1950s. I am trying to translate it but I am sure if I knew where to go there is a translation likely somewhere at the British Museum where the original likely still is if it survived World War I and II.

When I ran the first sentence through a French to English robotic translator at least half the words couldn't be translated which either means I misread them or they aren't used in this way anymore. So, for me at least without a classic French education I'm not sure if I'm doing it right.

If you are familiar what happened during the French Revolution to Nobles and to the rich it won't be a surprise to you that many Nobles and rich then as now often use aliases and disguises to protect their families and persons from harm. Some of the names the Comte de Saint Germain used that are still known are:

Comte De Saint Germain in 1710 witnessed by Countess D'Adhemar

Marquis de Montferrat in 1760 witnessed by Countess D'Adhemar
Comte Bellamarre in Venice
Comte Aymar in Venice
Chevalier Shoening at Pisa
Chevalier Weldon at Milan and Leipzig
Comte Soltikoff at Genoa and Leghorn
Graf Tzarogy at Schwalbach and Triesdorf
Prince Ragoczy at Dresden
and the Comte De Saint Germain at Paris, The Hague, London and St. Petersburg.

Also, since he was often used as a Spy at different times by the French Monarchy and sometimes the English as well it might be said that on some occasions he might have been a double agent? So, what is interesting to me is someone like the Comte who is often given the honor of founding the Masonic Order as a soul who is also Historical and mysterious, spoke almost all languages without any foreign  accent and also who was connected with the Philosopher's stone through either legend or reality and who Voltaire once said of, "He is a man who knows everything and who never dies!"

My reading of the letter as best as I can decipher it: Monsieur
corroifflants depuis longtems votre sont pour les livres, & le soir que vous prener der enricher continnellement voire belle nombreufe bibliotheque, j'ai ern que je vous perois plaisir je vous parler
j'une les plus rares & des plus lingulicres qu'en connoifle 

I ran that through Google Translate and here is what I got: begin translation

Mr.

corroifflants a long time since you are in books, and in the evening you than to take der enricher continnellement even nombreufe beautiful library I ern perois pleasure that I tell you I

I a the rarest & most lingulicres that connoifle. 
 end translation

Obviously, this is a letter likely thanking someone for some books at this point. However, missing so many words I don't really know more than this.

My daughter who has had 4 years of French at her  Prep School says we should take it to a friend who grew up in France to read for us and maybe to translate. It would sort of like reading the Declaration of Independence to someone and explaining it. Though it was written 237 plus years ago
we can still read it even though it isn't exactly the way we speak English anymore here in the U.S. I'm not comparing the Declaration of Independence to this letter. I'm speaking about how different we use languages (English and French)  now than we did in the 1700s in general.

Also, this obviously was only the first few lines of the letter and not the letter in it's entirety.