172 on making ice in Itidia. -^^S' ?• 



of the lining, and a thatched roof is thrown over the 

 whole. It is here ftecefsai-y to remark, that the 

 quantity of ice depends materially on the wea- 

 ther ; and consequently it has sometimes happened, 

 that no congelation took, place : at others, perhaps, 

 half the quantity will be frozen ; and I have often 

 seen the whole contents formed into a perfect 

 cake of ice. The lighter the atmosphere, and the 

 more clear and serene the weather, the more fa- 

 vourable for congelation ; as a frequent change of 

 winds, and clouds are certain preventatives. For I 

 have frequently remarked, that after a very {harp cold 

 night, to the feel of the human body, scarce any ice has 

 been formed ; when, at other times, the night has 

 been calm and serene, and sensibly warmer, the con- 

 tents of the pans will be frozen through. The stron- 

 gest proof of the influence of the weather appears by 

 the water in one pit being more congealed than the 

 same preparation for freezing will be in other situ- 

 atiohs, a mile or more distant. 



To reason physically upon this procefs of making 

 ice, it may be said, that, had the thermometer been 

 suspended in the air, free from every other body 

 ■ capable of communicating heat, in some parts of the 

 night during the cold months of December, January, 

 February, the quicksilver might hr.ve descended 

 to the freezing point, and that water, being artfully 

 placed in a similar situation, contained in thin po- 

 rous pans, and supported by a substance little capa- 

 ble of communicating heat from the earth, might 

 also freeze, and continue in a state of congelation till 

 the heat of ihe morning came on, I say this may be 



