l6 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. 



nearly in the following words : ' As to my beatification, I am highly obliged to 

 you for writing to me so freely and candidly about it ; and I will discover to you 

 my whole artifice without any retention, though I concealed the same from all 

 my friends and correspondents. Now, sir, it is true that I have embellished a 

 little my beatification by my style and expressions ; but it is also true, that the 

 basis of the phenomenon is constant. I found in our armoury at Leipzic, a 

 whole suit of armour, which was decked with many bullions of steel ; some 

 pointed like a nail ; others in form like a wedge ; others pyramidal. In the 

 dark, you well know, that not all, but very many, of the said bullions will 

 sparkle and glister with tails like comets : and it is clear, that when the electri- 

 city is very vigorous, the helmet on the head of the person electrized will dart 

 forth rays like those round the head of a canonized saint; and this is my beatifi- 

 cation. You are the first, sir, with whom I trust my mystery, which if you com- 

 municate to the R.s. I hope you will take care of its being inserted in the Phil. 

 Trans., that the beatification did not succeed until I communicated my method. 

 Many people have imagined this experiment of mine to be extravagant and false. 

 If the armour is not ornamented with steel bullions, I believe it will not succeed. 

 If the armour is well enriched with bullions, and well polished, the comets ap- 

 pear twice, once in the air, and once by reflexion from the armour. A stoma- 

 cher, or a doublet, set with nails or needles, will exhibit a small degree of beati- 

 fication.' 



Part of a Letter from Mr. Professor Euler, to the Rev. Mr. fVetstein, Chap- 

 lain to his Royal Highness the Prince, concerning the Contraction of the Orbits 

 of the Planets. Translated from the French byT.S., M.D., F.R.S. N° 

 494, p. 356. 



You have done me much honour, says Mr. E.in communicating an extract of my 

 last letter * to the illustrious r. s., November 2, 1749. I am still thoroughly con- 

 vinced of the truth of what I advanced therein, that the orbs of the planets con- 

 tinue to be contracted, and consequently their periodical times grow shorter. 

 But in order to put this fact out of doubt, we ought to be furnished with good 

 ancient observations, and also to be very sure of the time elapsed, since those 

 observations, to this day : which we are not, with regard to the observations 

 that Ptolemy has left us. For chronologists, in fixing the moments of those ob- 

 servations, ran into a mistake, by supposing the sun's mean motion to be known • 

 which ought rather itself to be determined by these same observations. Now 

 if we reduce the days marked by Ptolemy to the Julian calendar, we run the 

 risk of committing an error of a day or two, in the whole number of days elapsed 



• See Phil. Trans. N" 493.— Orig. 



