CALCAREOUS TUFAS, ETC. 



33 



Smites 



18. 



Con tainj( Marlstone. 



Crystals op calcareous spar lining a cavity, in 'Upper 



Dorset 



GALLlETt 



D 



19.— Calcareous deposit, formed in the condenser of a Wall " caEe40 

 steam engine, and obtained by John Dawes Esq. Smetli- 



wonihtH wick House, near Birmingham. 



20. 



ems of ci 



>f 



from the decomposition of the ores in the heaps of refuse of 



//we/ 



ed of 



fir 



tor char* 



with 



In this case the metalliferous matter has been partly de- 

 composed, and borne away in solution in the water that 

 percolated through the refuse heaps, after which it was re 

 upon sou deposited as carbonate of copper amongst the sand, thus 

 icans it i agglutinating the particles and forming a sand rock.— A.C.R. 



21.— Calcareous deposit formed on the heads of rivets 



^ 



i a copy: 

 ing pk 

 e gradual 

 ii t i on of 



Hippo, t 



lay sltf 



)!1. 



on 



i 



taining 



satin f 



Frome, Somerset. 



Factory 



22. 



« - ,r- t 7 Calcakeous deposit from the walis of the Fiscina 

 t of ii Mtrablle > near Naples.— Presented by Dr. H. C. Barlow. 



23.— Calcareous incrustation from the interior of a 

 boiler— Presented by Dr. Lyon Playfair, C.B., F R S 



Nos. 2, 6, 8, 8a, 19, 21, 22, and 23 illustrate the manner 

 in which pipes and other vessels become choked by depo- 

 sitions from hard water containing lime in solution. In 



•laysiaf London and aU otLer districtg supplied witIl Imrd waterj 



most persons are familiar with this circumstance by the 



) 



24. Part of a lode, consisting of angular fragments of 

 limestone, cemented together, and encrusted with crystals of 

 calcareous spar — Presented by Dr. Lyon Playfair, C.B., 



F.R.S. 



25— Calcareous incrustations upon the leaves of a 



tree. 

 26. 



•Travertine or calcareous tufa,* containing the 



impression of a leaf.— Matlock, Derbyshire. 



* See also Table-case in Recess 6, Nos. 206 to 223. 



B 





