JVoiice of the Smoking Sulphuric Jlcid. 347 



Sprengel's essential character of these united genera is " Flores 

 verticillati, bractcati. Calyx tubulosus, quinquefidus. Corolla \. 

 Stamina subsequalia, inclusa vel exserta." 



Our plant is therefore not a Pycnanthemum, either according to 

 Michaux, Pursh, or Sprengel. 



Art. XIX. — JVoiice of the method of manufacturing the smoldng Sid- 

 phuric Acid, as practiced at JYo7xIhausen, Braunlage and Tanne, 

 in Germany J by Thomas G. Clemson — in a letter to the Editor, 

 dated Paris, April 18, 1831. 



In the interior of our country, in places far distant from those in 

 which sulphuric acid is manufactured in the ordinary way, its use be- 

 comes expensive in consequence of transportation; among these pla- 

 ces, a coincidence of natural circumstances may permit of obtaining 

 the acid with advantage from the sulphate of iron. The easy con- 

 struction of the little necessary apparatus, the materials of which are 

 every where present, and the Ihtle expense attendant thereon, to- 

 gether with its particular uses, may suffice to raise this species of in- 

 dustry, hitherto unknown, (at least to myself,) in the United States. 



There are three Prussian towns, not far distant from each other, 

 where this acid is made from the sulphate of iron ; they are Nord- 

 hausen, Braunlage and Tanne. It is from the first named tliat this 

 acid has taken one of its names; the two latter places are more hap- 

 pily situated than the first; they are surrounded by forests, which 

 cover the highlands of the Hartz, and are not so far distant from the 

 locality where the decomposed pyrites of the celebrated Ramelsberg 

 are lixiviated. The oleum's hutte or manufactory of the smoking 

 sulphuric acid of Nordhausen, stands on the road that leads from 

 Zorge to Braunlage, not far distant from the latter place. The build- 

 ing is simple tiiid of stone, ventilated by standing blinds in the lateral 

 walls and roof, thus permitting the easy escape of smoke and other 

 more deleterious vapors. The building contains four galleries or fur- 

 naces, and each gallery sixty four cylinders or retorts, with as many 

 recipients. The whole is conducted by two workmen, the master 

 and his son. 



Fig. 1 is the elevation of the gallery. ABCD is die base, which 

 is in stone, being 1 metre and SO centimetres (72 inches English) in 

 breadth from A to B, and GO centimetres from B to C. E is the 



