i824.] Memoir on the Fumigation oj Letters. 231 



seilles, by mixing two-eighths of muri- spread in a cup ; I poured on it a mix- 



atic acid with three-eighths of sulphuric lure, ma<!e of equal portions of saltpetre 



acid. I oliserved that they both smelt and sulphur in powder; I placed the 



of the nuiriiitit; gas, less, however, than cup in tiie fire-place of the stove of 



in the experiments performed according Beaume ; and, in the grate, I placed two 



to the process of M. Morveau. letters, one of which was simply scaled, 



There was hardly any change of without being slashed, and the other 



colour in the blue paper. This experi- was hermetically closed: both the letters 



ment indicates, that the disinfecting contained some paper tinctured with 



process made use of lately at Marseilles turnsol. I set fire to the combustibles 



is less active ; and, consequently, infc- of the cup, by means of a red-hot iron; 



rior to that of Mr. Morveau. the letters were left in the stove for half 



It still remains for me to make some an hour; and, on opening them immedi- 



observatioDs on the fumigation of letters ateiy afterwards, I remarked that the 



by means of the combustion of sulphur; 

 which, of all known processes, is the 

 most ancient. His excellency, M. 

 Sousa, knowing that I was making some 

 experiments on the method of fumi- 

 gating letters, and having been informed 

 that they are fumigated at Malta with- 

 out being opened, directed Dr. Seixas, 

 sub-director of the elaboratory ol FHotel 



blue of the paper was changed into a 

 most lively rose-colour, and that the 

 writing had not experienced any altera- 

 tion. 



On comparing the results of all those 

 experiments, I drew the conclusions, 

 that letters may be disinfected without 

 opening them, by means of vinegar, 

 according to the process of M. Hor- 



de la Monnaie, to perform the process veau, and with the combustion of suL 



practised at Malta, and to submit the phur; that it is not necessary to open 



result to my examination. them; that, in making use of vinegar, 



Twentieth experimetit.— This process the letters must be dried by the fire ; 



consists in fumigating the letters with 

 sulphur and straw. Doctor Seixas 

 performed it in the stove of Beaume, in 

 which he left the letters for halt' an hour. 

 Some of these letters \vere hermetically 

 closed, as in tiie sixth experiment; 

 others were sealed in the ordinary man- 

 ner. Having opened them, I observed 



that the process of M. Morveau is less 

 uniform, and, consequently, more uncer- 

 tain than that of vinegar; that both of 

 them tend to injure the writing of the 

 letters; that, in adopting the process of 

 M. Morveau, it should be repeated and 

 prolonged until an alteration takes place 

 in the writing; that the fumigation of 



that the effluvium had fully penetrated sulphur is preferable to the other pro- 



them, because they preserved a very cesses, because it is more prompt, more 



strong odour, without excepting those unilorm, and less expensive. It is 



which were hermetically sealed; and, a requisite to know, that the criterion of 



month afterwards, an odour was still disinfection, according to this j)rocess, 



perceptible, which had a greater affinity consists in the sulphureous odours which 



to the burnt straw than to the sulphur. the letters acquire ; and that, in order to 



Twenty-first experiment. — I repeated impregnate them, it is sufficient to burn 



the twentieth experiment on the two a little sulphur with some saltpetre, so 



letters infected with the cadaverous that the sulphureous vapours are seen 



gas, o;;c of which was hermetically 

 sealed ; and, in the other, some incisions 

 were maile. Both of them contained 

 paper coloured with turnsol ; and, in 

 each of them, the cadaverous odour was 

 re[)laced by that of the effluvium : the 

 blue paper was changed to rose-colour. 

 As in the process the sulphur was not 

 well burnt; and, on the other hand, as 



to rise above the letters. 



R. H. 



To tiie Editor of the Monthly Magazine. 



SIR, 



IN perusing a treatise on " Domestic 

 Economy," I find that the plant 

 called CcEsarian hale is highly extolled 

 for its qualities; and have, in conse- 

 quence, made many ap|)lications in 



the straw might raise a llame to injure various quarters to procure the seed of 



the letters; I attein|)ted, by dillerent 

 methods, to find the means of avoiding 

 those two inconveniences. I succeeded 

 by the following experiment. 



Twenty-second experiment. — I took a 

 small quantity of hemp, which was well 



Monthly Mac No. 394. 



it, but without success. As the know- 

 ledge of where this may be had, is likely 

 to interest others besides myself, I shall 

 be very glad to have it elucidated by 

 the means I now take. Hortensis. 

 London, Fab. i), 1824. 



211 



STEPHEN- 



