Faraday to Benjamin Abbott   5 April 1813

Monday night April 5. 1813

Thanks to my dear Ben for his letter ‘twas so long since I had before obtained one from him that my pleasure was if possible heightened at the reception of it perhaps as much by the long and silent interval preceeding it as by the letter itself. There is no occasion for me to inform you that I feel influenced by the same hopes and fears as yourself ‘tho they are considerably abated by knowing that you will and that I intend if I can to support each out part. But before I proceed farther let me congratulate you on the safe and happy return of a beloved brother from a long and dangerous voyage after a tedious & extended absence and I feel much pleasure mental pleasure in knowing the increase of happiness that it will occasion in the breasts of his relatives[.] I cannot refrain from again desiring of you to remind him that there is such an one as myself who feels the most earnest interest in his welfare - just jog his memory so that he may not entirely forget me[.]

You desire me to inform you at times of any thing new in philosophy that may fall in my way and I shall accordingly obey your desires by detailing to you at present some circumstances relating to the newly discovered detonating compound¹ this I do with more eagerness as I have been engaged this afternoon in assisting Sr. H. in his experiments on it during which we had two or three unexpected explosions[.]

This compound is formed by inverting over a solution of the Nitrat or Muriate of Ammonia an air jar full of fresh made pure clean chlorine gas all contact of oil grease or inflammable matter being carefully guarded against it was at first supposed necessary to surround the solution with ice but it is of no importance to do so it in fact forms better without it.

Immediately that the gas is inverted over the solution an action commences this is evident by the gradual tho slow rise of the solution in the jar as the absorption of the gas takes place quickly spots are evident on the surface of the solution in the jar which increase in size and appear as drops of an high colored oil[.] As the action goes on these drops become so large as at last to fall from the surface and sink to the bottom of the solution[.]

I am not exactly aware what change it is that takes place in the solutions[.] In that of the Nitrate of Ammonia the action is not apparently so strong as in the other. the solution of the Muriate becomes as it absorbs the gas of a fine amber colour and a continual ascending shower of bubbles pass through its whole length. in the Nitrate of Ammonia the colour is scarcely at all affected and the action is not so energetic[.]

The substance in question possesses very many singular properties amongst which its immediate decomposition is not the least remarkable as soon as a globule is formed & has fallen to the bottom of the solution it begins to decompose this it does by giving off azote a minute bubble of gas appears at the top of the globule which when it has attained to some size separates & rises to the surface another is immediately formed which rises in turn & thus the whole may be decomposed this gas is ascertained to be azote[.]

The Specific gravity of this body appears to be very considerable that is to say three or four times as heavy as water during its spontaneous decomposition the bubble of gas will sometimes carry up with it to the surface the globule of the compound but becoming separated at the surface the globule falls with considerable rapidity through a strong solution of the Muriate of Ammonia a salt not deficient in solubility & of course the solution is somewhat dense[.]

At the bottom of the solution or of water the globules appear to exert a considerable power in the attraction of aggregation and they there appear compact close & dense but if a small portion happens to rise by the gas attached to it and gains the surface and contact of the atmosphere it immediately expands as would oil and quickly evaporates and is lost in this state that is whilst evaporating it affects the eyes in a very disagreeable manner bringing forth tears in abundance it excites also a very disagreeable sensation in the nostrils and lungs.

It appears therefore that this body quickly assumes an elastic form and this afternoon I witnessed its solidification a portion of it in the solution was placed in a freezing mixture of ice and the Muriate of Lime the compound quickly became solid and appeared like butter in cold weather and the solution itself appeared to freeze sooner in consequence of its having dissolved a small portion of it. Alcohol or spirits of wine dissolve this compound very readily but I have not seen the solution.

With respect to its detonating power it exhibits them with many bodies when a small portion of it is placed in a bason and covered with water and oil or Phosphorus is then brought in contact with it it explodes violently the bason is shattered to pieces and the water is thrown in all directions but I can inform you of a very easy and safe method of inflaming it by oil which is thus drop a small portion of it on an oily surface and an instantaneous inflamation will ensue but without noise[.] Heat also explodes this body and was by this means that Sr. H. met with his very unpleasant accident²[.]

Another mode of exploding it was discovered this afternoon in the Laboratory here but I must first inform you of the other experiments[.] Having made a considerable quantity of the compound and gathered it together (that being my business) Sr. H. proceeded to make his experiments on it and first with the acids[.] A small glass was filled with Muriatic Acid and a tube closed at one end and answering the purpose of a receiver was filled and inverted in the same a globule of the compound was then introduced into the glass and the end of the tube placed over it the rapidity with which the globule was decomposed increased very much bubbles of gas rose in quick succession which expanded as they ascended in a beautifull manner to fourteen or fifteen times their original bulk and the tube quickly became full of gas this gas was transferred to a water trough examined and found to be pure chlorine excepting about one fortieth part of pure oxygen gas. on examining the Muriatic Acid in which the decomposition had taken place Muriate of Ammonia was found to have been formed[.]

When the compound was tried in the same way in Nitric Acid Azote gas only was formed[.]

The same gas was given out when it underwent spontaneous decomposition in a solution of pure potash but when decomposed in Ammonia it was decomposed indeed[.] Sr. H bade me repeat the experiment with Ammonia as I had done with the Acids accordingly a glass was filled & a tube inverted and then a portion of the compound was introduced but lo! instead of sinking to the bottom it rose to the top a strong action took place and a considerable quantity of smoke was produced[.] As it was evident the body was decomposed it shewed that something could be done in this way and therefore we modified the arrangement of circumstances a little glass was filled with water a tube full of liquid ammonia inverted in it a globule was then put in the glass which sank to the bottom and the tube was placed over it a bubble of gas formed which ascended in the tube and at the top appeared like smoke a second rose and inflamed in the middle of the tube the compound being all decomposed I put in a much larger portion a bubble formed in it which in rising took up the globule of the compound with it it ascended within about one third from the top when an explosion took place and the vessel was shattered to pieces[.]

So far has Sr. H proceeded with his experiments on this body and so far have I got on in my letter he has ceased his experiments untill tomorrow and I must cease scribbling until another time[.] This letter I know is too long but I will not increase its length by apologising. I am

dear Abbott | Yours truly | M. Faraday

I had almost forgot an important part of my letter. Robert wishes to know how you are engaged for next friday week but it is scarcely possible to arrange anything without verbal communication if you will give me leave I will call on you some evening this week[.] I would ask you here but that Sr. H. goes out of town next monday³ which renders his presence here more continual at this time besides I hope to see both you & your Brother here in his absence when I shall be more at liberty[.] I wait your answer. Farewell.

Address: Mr. B. Abbott | Long Lane | Bermondsey