28 On the Presence of Muriatic Acid [July, 



in these cases by deoxidizing the salts of silver and gold. Nei- 

 ther muriate of platina, nor protonitrate or pernitrate of mercury, 

 were acted upon by steam in a similar manner. 



The observations of the Dutch chemists, which are scattered 

 in a number of different dissertations, have been collected and 

 again published by Dr. Driessen,* and they possess great inte- 

 rest. Prof. Driessen, of Groningen, made the first experiments 

 in July, 1800, at Amsterdam, where he poured several ounces of 

 pure water 500 times through a glass funnel from one vessel into 

 the other. The water sometimes exhibited a slight trace of sul- 

 phuretted hydrogen, but it constantly threw down nitrate of 

 silver, of a white colour. These experiments were made at dif- 

 ferent hours of the day, and in different heights above the 

 ground, but constantly with the same result, if it had not rained 

 for a considerable time. When, however, M. Craanen, who had 

 been present at these first experiments, tried them again after 

 rainy weather, he did not obtain any precipitate at all. In Gro- 

 ningen, he did not find any muriatic acid in the air, except once 

 in 1802, when, after a long dry season, a thick fog came on; 

 water which had been poured in the way above-mentioned, 

 occasioned a precipitate in nitrate of silver, and reddened even 

 tincture of litmus. Dr. Von Rossem could not afterwards detect 

 any trace of muriatic acid. 



The fact that the air near the sea-shore contained free muria- 

 tic acid was applied to explain the frequency of that dreadful 

 disease the colica saturnina, at Amsterdam, where it had been 

 observed oftener than in any other town. It was conceived that 

 the free muriatic acid dissolved the lead from the roofs of houses, 

 and communicated it to the rain water. 



A new series of experiments was, therefore, performed by Dr. 

 Veehof in order to ascertain whether the muriatic acid was 

 really in an uncombined state in the atmosphere ; and the results 

 were, that water poured from vessel to vessel at Groningen in the 

 manner already mentioned, and rain-water from the same place, 

 contained no free acid ; that water similarly treated near salt 

 springs showed a slight trace of free acid ; and lastly, that water 

 at Amsterdam, under the same circumstances, contained a con- 

 siderable quantity of uncombined acid. 



These experiments were twice repeated, and constantly with 

 the same result. They all showed muriatic acid by nitrate of 

 silver, but that from Amsterdam most of it. Besides the water 

 from Amsterdam produced a precipitate when tried with muriate 

 ofbarytes, and caustic alcali occasioned a more copious preci- 

 pitate in it than in water, treated in the same way at Groningen. 



Prof. Driessen repeated his experiments in 1809 at the 

 Zuider Zee, where, after having poured the water more than 

 1000 times from one vessel to another ; while the direction 



• Schweigger's ^(ew Joujiial, b. 6, «. 1822, 



