Faraday to John Franklin   17 May 1826¹

Royal Institution | May. 17. 1826

My dear Sir

Through the kindness of Mr. Moore I have a short notice of the sailing of the Hudson’s bay ships and thinking with him that a letter will give you but little trouble and may perhaps afford a moment’s amusement I am to write not merely at his request but through my own strong inclination[.] When absent from England only 12 or 15 months I have enjoyed the pleasure of a letter from any one in it persons at other times of but little importance then becoming quite interesting and considering how entirely you have sacrificed personal ease and comfort for deprivation and pain cold must be the feelings of those who having any hope of cheering you for a minute would let it die away unheeded & unused.

I had occasion the other Evening to refer to you at a meeting of the members of this house and to the little experiments I placed in your hands² and I have also had occasion to quote them in a paper to the Royal Society[.]³ It is probable you may not have time or fitting opportunity to make them but I have pursued the subject here both by experiment and argument as far as I can and I am happy to say to the satisfaction of Dr. Wollaston - My Object has been to prove that a limit exists to vaporization beneath which bodies give off no vapour but are absolutely fixed. It is generally received opinion that such limit does not exist - that all bodies give off vapour but diminishing with the temperature and fixedness of the body (using that term in its common sense) and being in some cases of extreme tenuity[.] Now I try to shew that at certain possible temperatures for certain bodies the tension of the vapour is so small as to be inferior to either the force of gravity or to the force of aggregation and that consequently it must give way to them or either of them and entirely disappeared and if this is true it is evident that below such temperatures the bodies cannot give off vapour.

I think too that I have shewn with respect to mercury and sulphuric acid that the points of fixidity are above 0° of Fahrenheit and I am in hopes the experiments you may make for me will prove the existence of the limit as respects sulphur iodine camphor &c &c or at least will indicate something[.]

We have been very active in our Institution this season and have established converzatziones on Friday Evenings which have been numerously and well attended[.] We light up the house bring forward a subject in the Lecture room illustrated by experiments diagrams models &c and this serves as matter for the Evening. We then adjourn to the library where we take tea and seldom part till 11 o clock or past[.] Last Friday we had a very interesting subject being an improvement by Lieut Drummond on the means of effecting geodesical operations⁴[.] In consequence of the obscurity of objects when seen through a haze or even what appears to be a clear atmosphere it was desirable that some object should be contrived that would have as it were power of penetration in such case lamps & mirrors were found very ineffective but Lieut Drummond has succeeded admirably by placing a ball of lime in the focus of a parabolic reflector & raising it to an intense heat by alcohol lamp urged by oxygen g<<as.>> The light thus obtained is so dazzling that a person on to whom it is thrown at the distance of 50 or 100 feet cannot see the form of the mirror[.] Its intensity had risen as high as 90 that of an Argand lamp being 1 only. It has been very successfully applied in the survey of Ireland⁵.

I have written nothing to you about what is passing elsewhere, I have no doubt all that will be told you by others. We are making a hard struggle to restore the Institution and I have no doubt you will find it when you return in a very different state to that you left it in. Mr. Moore is as usual astonishingly liberal[.]

I am Very Dear Sir | Your faithful Admiring Servant | M. Faraday

Address: Capn Franklin R.N. | &c &c