28 



HARDWICKE'S SCIENCE-GOSSIP. 



occur there in such abundance that the strata can be 

 identified by their remains. The dry land everywhere 

 was covered by a flora much resembling in its general 

 characters that of the Carboniferous epoch. This 

 is the last we see of the familiar coal forms, for 

 others were already in existence, destined soon to 

 replace them, and render them extinct. Thus much, 

 therefore, for the dim recollections of a piece of 

 Hock-salt ! 



ICE IN THE TROPICS. 



(With Notes on Methods of Refrigeration.) 



TN the hot season of 1816, when I first visited 

 -*- Benares, North- West Provinces, India, I was 

 much surprised at seeing placed before me at dinner 

 a Nesselrode pudding, and at finding that all our 

 liquors were iced. I inquired how this was done, 

 expecting to find that saltpetre and Glauber's salt, 

 which I heard were often used for cooling pur- 

 poses in India, had been employed. But judge of 

 my astonishment when I was told that ice had been 

 used, and that the said ice had been manufactured 

 at Benares, where the thermometer seldom, if ever, 

 falls so low as 42° Pahr. 



I will presently give a short account of the 

 manner in which it is obtained ; but I will first 

 gossip a little about the various methods of cooling 

 beverages, &c, in common use, where ice cannot 

 be obtained in India. 



1st. Tatties, or screens made of khas-khas grass, 

 are placed in the window-frames, and by water being 

 thrown upon them the fierce hot winds create a 

 great coolness inside them by forcing themselves 

 through the interstices, having become cool through 

 the rapid evaporation of the water, which process 

 produces intense cold. 



On the lee side are placed plates of fruit, bottles 

 of water, wine, &c., which are well cooled in this 

 manner. The "khas-khas" consists of the roots of a 

 sort of grass with an aromatic odour, found growing 

 in sandy places (Aiulropogon veterina). 



2. But in many places khas-khas cannot be ob- 

 tained, and I have then seen bottles of water, wine, 

 beer, &c., placed in loose straw in open-work wicker 

 baskets well sprinkled with water, attached by a 

 rope to a high bough, and swung violently to and fro 

 in the hot, still air, whereby a very considerable 

 degree of coolness has been imparted. This, of 

 course, was caused by the same rapid evaporation 

 in a hot current of air. 



3. Again, frames are constructed of grass or 

 khas-khas, to swing backwards and forwards, with 

 places made in either side for bottles, which were 

 kept well watered. 



4. But yet, again, another way. Water is placed 

 in a porous jar or " soraiee "—such as the GennMi 

 jars of Egypt — wrapped round with a wet cloth 



and placed in a hot place. This rapidly becomes 

 cool, as do the bottles which stood in it. 



5. Next to ice the best thing is a mixture of salt- 

 petre and Glauber's salt — I believe about \ of the 

 latter to f of the former. These are dissolved in 

 water, and, whilst dissolving, the bottle to be cooled 

 is shaken violently about in the liquid, whereby 

 great cold, even to freezing ices, is produced ; and 

 for many years our ices were so prepared in their 

 moulds for table use. 



But, to return from this digression, I will relate 

 how the ice is obtained at many up-country stations 

 in the North- West Provinces of India ; and as the 

 railway is now bringing Wenham Lake ice, imported 

 via the Presidency towns, into more general use, 

 it may be worth placing on record as a thing 

 becoming rapidly obsolete. 



Prom my inquiries, there is every reason to believe 

 that the great Akbar had his ice prepared in the 

 same manner at Agra, and the natives now manu- 

 facture it as well as Europeans. 



The residents at a station generally club together, 

 raise a fund, and place it in the hands of some 

 energetic member, who proceeds as follows : — 



He builds an ice-house and lays out ice-fields. 

 This ice-house consists of a pit, some fifteen feet in 

 diameter aud as many in depth, dug in as dry a 

 place as can be selected, on a level spot not too 

 exposed. This pit is liued with double planking, 

 with chaff well rammed between the two sets of 

 boards; whilst, to increase the non-conducting 

 power of heat of the sides, a lining is generally put 

 in, consisting of a thick rope of tightly-tied up straw 

 or stalks, wound round and round interiorly. 



Arrangements by 'pumping or dipping arc also 

 made for keeping the space clear of the water which 

 accumulates at the bottom, owing to the melting of 

 the ice. 



Over this ice-well there is erected a round house 

 with very thick walls, sometimes single and at 

 others double, whilst over all is a very thick conical 

 thatch. A small door completes the building. 



Into this the ice is brought as collected in large 

 baskets as fast as possible, and men are employed 

 to beat it down, so as to consolidate it ; and upon 

 this ice, so stored, depends the luxury of cool be- 

 verages in the hot weather. 



But now to its manufacture. 



The level ground is laid out in broad walks, and 

 these intersect one another at right angles, forming 

 large beds. These beds are again subdivided into 

 smaller ones, of, perhaps, 10 feet square. At the 

 points of intersection are placed large earthen tubs 

 filled with water, and by them arc large heaps of 

 small shallow saucers, of, perhaps, 5 or G inches in 

 diameter and 14 inch deep. The level of the beds 

 is about 4 or 5 inches lower than that of the paths. 



Hard by stands a large stack of straw, and many 

 baskets, large and small, are ranged alongside. 



