Lavoisier, Revolutionary: 3. A letter to Franklin (1790)

 There was no denying Lavoisier had a close call in 1789; he can have been left in little doubt that his personal position remained vulnerable. Nonetheless, by early 1790 the cause of Constitutional monarchy seemed to be triumphant. The spectre of popular revolution had receded and power appeared safely consolidated in the hands of Lavoisier's friends and allies.  He looked forward to the work of national regeneration which lay ahead.

A rare piece of evidence as to Lavoisier's state of mind at this time is provided by a letter dated 2nd February 1790 written to Benjamin Franklin. Lavoisier informs his illustrious correspondent that the Revolution has succeeded but expresses regret that popular armed intervention had been necessary.  One sense a certain unease: 

After telling you about what is happening in chemistry, it would be appropriate to give you news of our political revolution. We look upon it as successfully and irreversibly accomplished. The aristocratic party still exists and offers some useless resistance, but it is evidently the weaker.  The democratic party is in the majority and is supported by the educated, philosophically-minded, and enlightened members of the nation.

Persons of moderate opinion, who kept their sang-froid during the general excitement,  think that circumstances have carried us too far. They consider it very unfortunate that we were compelled to arm the people and all the citizens.  It is not good political practice  to allow the employment of force by those whose role is to obey.  It is to be feared that the new constitution will be obstructed by the very people for whose benefit it was created.... We greatly regret your absence from France at this time; you would have been our guide and would have marked out for us the boundaries that we should not cross.

Translation from the Edinburgh Review (1890), p.98  ["Even while announcing to Franklin, the "successful and irreversible accomplishment" of the political revolution in France, it is plain that Lavoisier was troubled, in his view of the rising sun of democracy, by some vapour of misgiving..."]

On July 5th, Lavoisier wrote, equally revealingly, to the Scottish chemist Joseph Black: 

The state of public affairs in France during the last twelve months has temporarily retarded the progress of science and distracted scientists from the work that is most precious to them; but we must hope that tranquility and prosperity will follow the troubles through which we have passed and which are inseparable from a great revolution.  
(Reproduced in Grimaux, Lavoisier p.201-2)

Franklin himself was not so sanguine. On 13th November 1789 he had written to his friend, the physicist Jean-Baptiste Leroy, in some panic over the situation in France: 

“Are you still living? Or has the mob of Paris mistaken the head of a monopolizer of knowledge, for a monopolizer of corn, and paraded it about the streets upon a pole. Great part of the news we have had from Paris, for near a year past, has been very afflicting. I sincerely wish and pray it may all end well and happy, both for the King and the nation.  The voice of Philosophy I apprehend can hardly be heard among those tumults.  If any thing material in that way had occurred, I am persuaded you would have acquainted me with it. However, pray let me hear from you...a year’s silence between friends must needs give uneasiness. 
Private correspondence, vol. 1, p.265.
(It is this letter which contains Franklin's memorable bon-mot that nothing can be certain "except death and taxes").

Franklin died on 17th April 1790, and so, perhaps fortunately, was spared knowledge of the Revolutionary excesses to come.

References

Lavoisier, Letter no.1230 to Frankin, from Correspondance, (vol. VI - 1789-1791), followed by the manuscript.  Made available on the Academy of Sciences website.
https://www.academie-sciences.fr/pdf/dossiers/Franklin/Franklin_pdf/Lavoisier_Franklin_lettre.pdf

Publication of Lavoisier's correspondence is being  undertaken by the Comité Lavoisier of the Academy. There are more than  than 2,000 letters in total.  Vol. 6, which covers the period 1789-91, appeared in 1997 and vol. 7, for 1792-94, in 2012.  Both volumes were edited by Patrice Bret, who is General Secretary of the Comité Lavoisier. For details, see  http://historyofscience.free.fr/Comite-Lavoisier/f_correspondance.html

See also Douglas McKie, "Antoine Laurent Lavoisier, 1743-1794" Notes and Records of the Royal Society of London, 1949, Vol.7 (1): p.1-44. 
https://royalsocietypublishing.org/doi/pdf/10.1098/rsnr.1949.0001

This article contains transcripts of letters between Lavoisier and his English and Scottish correspondents, which were among the documents confiscated by the Revolutionary government in 1793.  The letters illustrate well both the international scope of Lavoisier's scientific network and the dangerous ambiguity of his contacts outside France during the Revolution. 

On the friendship between Lavoisier and Franklin, and their joint involvement in the investigation of Mesmer:
 Denis I. Duveen and Herbert S. Klickstein, "Benjamin Franklin (1706) and Antoine Laurent Lavoisier (1743-1794)" - 3 articles in the Annals of Science for 1955 [open-access article]

 https://www.tandfonline.com/doi/abs/10.1080/00033795500200115