Dr. lire on Disinfection. 89 



carbonic acid ; for air, carbonic acid, and chlorine are in spe- 

 cific gravity respectively as 2, 3, and 5. We need not be 

 told that chlorine, like other gaseous matter, has the faculty of 

 diffusing itself slowly upwards through atmospheric air; but 

 this is only when it has nothing else to do, for when it encoun- 

 ters substances on which it can exercise its pre-eminent affi- 

 nities, it will combine with them, probably to their destruction, 

 and certainly to its own, as an influential gas. In proof of 

 this position, I have many experiments to adduce, one of 

 which was exhibited before the Marquess of Lansdowne, Sir 

 Henry Halford, and the whole Board of Health in the Royal 

 College of Physicians, on Friday evening, the 24th of June. 

 Having had the honour, two evenings before, to submit to that 

 Board a plan for disinfecting the cargoes of ships, by dis- 

 tributing dilute chlorine through their holds by the apparatus, 

 figured No. 1, illustrative of this paper, doubts were strongly, 

 and very naturally, expressed by many members of the Board, 

 as to the penetrability of dense bales of hemp, wool, and 

 cotton by the chlorine gas. I was asked, whether I could 

 satisfy them on this head by an experiment ; and if so, how 

 soon. I undertook to make the experiment in two days ; but 

 an anxiety being shown to have it tried next day, I promised to 

 do my endeavour, with such apparatus as I could command. 

 Accordingly, on the 23rd of June, at four o'clock P.M., minia- 

 ture bales of hemp, wool, and cotton were made up as dense 

 as possible, the latter two being moreover inclosed in thick 

 canvas bags. They were all put into a tali glass cylinder, 

 open at top, the hemp being placed at the bottom. Chlorine 

 was now introduced through a glass tube, which descended 

 beneath the middle of the jar. In the centre of each parcel, a 

 bit of moist litmus paper was placed before it was bound up. 

 Next evening at nine o'clock, the Board having met again, the 

 little bales were opened, and the papers in their centres were 

 rendered snow-white, clearly proving the penetration. The 

 external fibres of the hemp parcel were so corroded by the 

 chlorine as to be easily torn asunder ; while the fibres of the 

 canvas bags, placed above, were not in the slightest degree 

 affected, nor the wool and cotton within them. I have since 



