PL ASTER OK PARIS 



LIME 



CALCIUM SULPHATE 



n< lit ion. This absorbs water and thereby expands 33 per cent. The 

 materials are in consequence continuously displaced, and the 

 ud Gorge may, therefore, be said to be in a state of constant 



Indust rial 

 Uses. 



Manure. 



Iii Rajputana, at Nagor in Jodhpur, a bed of gypsum probably not RajpuUn*. 

 i;in 5 feet thick has been worked to some extent. A similar ocrur- 

 is worked at Jamsar in Bikanir State. While excavating a well at 

 'alotl, gypsum of a very pure kind was found, but at too great a depth to 

 of much value. In the Panjab (Bannu district) the mineral occurs in Hanjab. 

 labagh and in Khasor, but is not utilised. The Kohat district contains 

 um in great abundance. Ball says " it might be obtained by open 

 g in any quantity, but is not worked." The Salt Range possesses 

 um in enormous quantity, associated with rock salt. The Spiti Valley 

 gypsum of a snowy whiteness. In the United Provinces deposits of u. Pror. 

 uypsum have been reported as met with in Dehra Dun, Kumaon, and 

 Garhwal. Middlemiss (Rec. Geol. Surv. Ind., 1889, xxii., pt. 2) gives a 

 full account of the gypsum of Nehal Nuddi in Kumaou. [Cf. Hayden, 

 Mem. Geol. Surv. Ind., xxxvi., pt. 1, pi. 16.] The Pioneer (July 27, 1888) 

 announced that gypsum had been found at a locality some 19 miles distant 

 from Haldwani, a station on the Rohilkhand and Kumaon Railway. In 

 Burma gypsum has been found, but not in sufficient quantity to be of much Burma. 

 >mmercial importance. 



Industrial and Agricultural Uses. For a great many years gypsum 

 been regarded as a manure of exceptional merit, especially for legu- 

 ous crops and for certain soils. It has recently been found to vastly 

 crease the yield of indigo, so that a large demand seems likely to arise 

 r it. The reader should consult the observations already made (p. 53) 

 regarding the use of this salt as a neutralising agent, or rather one which 

 modifies the physical conditions of the soil as to bring it into a cultur- 

 rble state. Of manures that contain gypsum mention may be made of 

 ' superphosphate," which is a mixture of calcium sulphate with an acid 

 hosphate of lime the essential manurial constituent. It is prepared by 

 e treatment of phosphatic minerals with sulphuric acid (Mukerji, 

 andbook Ind. Agri., 1901, 569-71). 



The next most important use for gypsum is the numerous methods 

 utilising plaster of Paris. In 1852 Dr. Buist drew attention to the 

 teresting fact that the Natives of Sind had, from ancient times, been sind Lattices. 



the habit of casting lattices and openwork screens to be used 

 ithin houses to allow of free circulation of air. The Marwaris very 

 leverly make what might be called stained-glass windows by taking Rajputana 



o lattice screens, made of plaster of Paris, of identical pattern, and yft*j^ 

 placing between these fragments of coloured glass so arranged as to bring 

 out the desired colour in design. The screens are then firmly fastened 

 together and the pieces of glass secured in their positions by a thin 

 layer of liquid plaster being run over the lattice upon which the glasses 

 ve been arranged before pressing home (on the top) the second layer 

 of lattice. In many parts of Rajputana and of the Panjab the walls 

 and ceilings of palaces are richly ornamented, in arabesque design, with 

 glass. These are silvered behind or backed with plated metal discs or 

 with coloured tinfoil, or they are painted on the surface and embedded 

 singly or collectively in wooden frames, within a plaster, which consists 

 xnainly, if not entirely, of plaster of Paris. This work might be described 



717 



