386 



NEW ENGLAND FARMER. 



Aug. 



bl3. The gentleman, observing no signs of the repulsion. Bodies exist in three forms, as solids, 

 predicted storm, ridiculed the boy's notions, and liquids, and gases. When the attractive force pre 



proceeded. In the course of two "hours, however, 

 he was retracing his steps completely drenched, 

 and found the J)oy eating his dinner in a little hut 

 near where he had left him. Curiosity as to the 

 source of the knowledge which he had found thus 

 verified prevailed over Jiis desire for speedy shelter, 

 and he stopped his horse, and offered the boy a 

 guinea to enlighten him on this point. The boy 

 took the guinea, and pointed to the closed flowers 

 of the Scarlet Pimpernel, some plants of which 

 happened to be growing near the hut. The gen- 

 tleman himself had written about this very fact, 

 mentioning that its open buds betokened fiiir 

 weather and its closed flowers abundance of rain, 

 and hence its title to its common name of Shep- 

 herd's Weather- Glass. Fully satisfied, he rode 

 on. 



^ We all allowed that there was some sense in this 

 sign, and that it could be ascribed to the instinct 

 with which nature endowed her children, to guard 

 them from injury. 



"But are there not," said my aunt, "some con- 

 trivances made to foretell rain 1 I have seen a long 

 glass tube filled with quicksilver, to which there 

 was a dial-plate attached, and the rise and fall of 

 the quicksilver regulated the hand on the dial, so 

 that changes of weather could be told. I do not 

 see why the boiling away of the water from the 

 potatoes may not be as good a sign as the rise and 

 fall of the quicksilver." 



Again there was a laugh at the comparison of 

 the vpater around the potatoes with the handsome- 

 ly-finished and expensive philosophical instrument 

 termed a barometer. 



The weather continued as pleaeant as before, so 

 last evening I packed up my carpet-bag, and made 

 the necessary preparations, requesting them to 

 wake me at five o'clock, and have the carriage 

 ready in time to convey me to the depot. 



I awoke this morning, and all was still in the 

 house. Quite pleased to be beforehand with them, 

 I looked at my watch, and with some difficulty, on 

 account of the dim light, found it to be fifteen 

 minutes after six. Much surprised at not having 

 been called, I jumped up, and threw open one of 

 the blinds of the window, but directly closed it 

 again, as a driving rain poured in. The reason 

 why I had been permitted to sleep on was evident 

 enough. I dressed, and went down to the break- 

 fast-table, where sat Aunt H. enjoying her tri- 

 umph. 



^ On my return to my study, forced as it were by 

 circumstances to do so, I began to reflect on the 

 boiling away of the water from the potatoes, and 

 tried to discover whether the ensuing rain was 

 mere coincidence, or due in some way to cause and 

 effect ; whether in reality connected with it or not. 

 The result of my deliberations and subsequent 

 conviction of the connection of the phenomenon 

 with rain I will now proceed to give. 



The pressure of the atmosphere, which is about 

 fifteen pounds to the square inch, forces many sub- 

 stances to retain the liquid condition that would, 

 were that pressure removed, assume the form of 

 gases. Of this, ether is an example. 



Chemistry assumes that all matter is made up 

 of exceedingly small particles called atoms, and 

 that around every atom there are two atmospheres, 

 the inner one of attraction and the outer one of 



dominates, the form is a solid ; when the attrac- 

 tive and repulsive forces are balanced, the form is 

 a gas. Caloric, or the principle of heat, is consid- 

 ered by many, and perhaps rightly so, as synony- 

 mous with the repulsive force. Hence an increase 

 of heat will make the solid become fluid, and the 

 fluid become gaseous. Thus ice changes to water, 

 and water to steam. 



The atmosphere, by its pressure, assists the at- 

 tractive force in the same manner that heat assists 

 the repulsive, the pressure and heat, of coui'se, act- 

 ing in opposite ways. Whatever, then, would 

 lessen the amount of pressure, would enable the 

 heat to act more powerfully. A certain amount 

 of heat, under the ordinary pressure of the atmos- 

 phere, is required to convert water into steam. 

 The less the pressure, the less the heat required; 

 but if the same amount of heat is applied to the 

 same quantity of water, under such circumstances, 

 the more rapidly will it be evaporated, or, in other 

 words, boiled away. It is evident, enough, then, 

 that if the atmospheric pressure is less at times 

 preceding rain, the water will boil away more rap- 

 idly than usual from the potatoes. 



I was frequently puzzled in my boyish days by 

 the assertion in scientific books, that the air is 

 hghter in rainy than it is in dry weather. It 

 seemed to me as if the air at such times should be 

 heavier, as, in addition to its own substance, it 

 holds suspended abundance of heavy clouds, which 

 uiust surely increase its weight. For many years 

 the problem remained unsolved in my own mind, 

 as it is yet unsolved, perhaps, in the minds of many 

 who read this. At last the thought occurred to 

 me, that as the weight of the air per se must re- 

 main the same at all times, taking it as a whole, 

 did it not really contain more moisture in solution 

 in clear than in rainy weather? And such is real- 

 ly the fact. As water, by the addition of salt, can 

 be made dense enough to float an egg, and as the 

 more the brine is diluted with fresh water, the 

 deeper will the egg sink in it ; so is the air, by 

 holding water in solution, rendered dense enough 

 to float clouds at a great height, and the greater 

 the amount of water it loses, the lower do the 

 clouds fall. This very dryness of the air is, in fact, 

 one of the many circumstances that cause rain. 



The air then is lighter, the pressure consequent- 

 ly less, and the unusually rapid evaporation of 

 water from the potato-pot is as good and trust- 

 worthy a sign of approaching rain as the falling of 

 the mercury in the barometer ; and thus the cook 

 in the kitchen may foretel as confidently as the 

 natural philosopher in his cabinet. And yet more, 

 for nature is bountiful : even where the apparatus 

 of the kitchen and the cabinet are denied, she fur- 

 nishes, without expense to her faithful observers, 

 means even more certain ; for the shepherd boy 

 has an unerring guide in the Scarlet Pimpernel. — 

 Plow, Loom and Anvil. 



d^" The Australian Movement. — The London 

 correspondent of the Philadelphia jYorth American 

 states that emigration to the Australian colonies has 

 almost entirely ceased, but shipments continue ac- 

 tive. The vessels now in the port of London under 

 despatch to the colonies amount in number to 73, 

 and iu tonnage 4i,G57 tons. Freightage is much 

 lower. 



