mo.] THE SOUTHERN PLANTER. 499 



In connection with this subject, permit 

 me, before I conclude, to say a few words io 

 relation to the objections frequently urged 

 hy us small farmers against the purchase of 

 labor-saving implements. The most of us 

 are staggered at the bare mention of invest- 

 ing a hundred dollars or so in tne purchase 

 of a macl^ine; and rather than thus dispose 

 of so much of our hard earned savings, we 

 are content to plod along in the same old 

 sluggish, slovenly track of our "illustrious 

 ancestors." The wonder is, that those of 

 lis who entertain such narrow-minded no- 

 tions do not stiil hitch our plows to the 

 horse's tail for the sake of saving the ex- 

 pense incurred in furnishing him with gear. 

 It "never seems to enter the brain of sorne 

 of us that by spending moiaey, especially in 

 procuring machines, we might possibly 

 make money. A thought pi-opelied upon 

 the swift wings 'of an electric 'Sash could 

 not beat a oonviction to this effect into such 

 microscopic brains. Although many of us 

 possess land peculiarly adapted to the use 

 of the Drill, and seed every year of our 

 lives in small grain, an area extensive enoi^gh 

 to justify its use, yet, rather than extract 

 from the corners of our old "chists" a hundred 

 dollars of idle money to expend in the pur- 

 chase of a useful machine, which would re- 

 pay us with double compound interest for 

 the investmecat, we seem to rest satisfied with 

 ■a practice that incurs an annual loss by the 

 want, more than equal iu amount to theeost 

 of the best niachines. Until we nam be di- 

 vested of su'ch narrow-minded notions, and 

 follow up the improvements which agrioul- 

 ture, as an art, is constantly developing, and 

 is still profitably susceptible of, we may always 

 expect to be singing that same old monoto- 

 aious soog ef hard times. 



" Chuckatuck." 



Meteorology. 



Dew and hoar frost. — Whea a mass of 

 moist air is brought in contact with a cold 

 body, its vapor is condensed into water and 

 deposited io minute globules on the cooled 

 surface, which constitute dev7. If the tem- 

 perature of the surface is below ihe freez- 

 ing point, the globules of water will be fro- 

 zen into minute crystals of ice, which con- 

 stitute hoar frost. For a long time the na- 

 ture of these phenomena was entirely mis- 

 oonceived ; the effect was put for the cause, 

 ike dew beiag regarded as producing the 



chill which accompanies its formation, in- 

 stead of the reverse. Dr. Wells, of Lon- 

 don, born in South Carolina., was the first 

 who gave the subject a scientific investiga- 

 tion, and, by a series of ingenious, accurate, 

 and conclusive experiments, furnished a de- 

 finite explanation of all the phenomena. 

 They are simply due to the eoid produced 

 in different bodies by radiation. As we 

 have seen in our essays in previous Reports 

 of the Patent Ofhce, the earth is constantly 

 radiating heat into celestial space, and is 

 constantly receiving it from the sun during 

 the continuance of that body above the ho- 

 rison. As long as the heat from the sun 

 exceeds that radiated into space, the tem- 

 perature of the surface of the earth and 

 that of the air i^i contact with it eonti?iues 

 to increase ; but when the two are equal, 

 the temperature remains stationary for a 

 short time, and then begins to decline as the 

 heat of the sun, on account of the obliquity 

 of the rays, becomes less than the radiation 

 into spaee. The maximum of heat gene- 

 rally takes place between 2 and 3 o'clock in 

 the afternoon, and the cooli«g from this 

 poiRt goes on until near sunrise of the next 

 morning. As soon as the sun descends be- 

 low the horizon, the cooling of the surface 

 of the earth takes place more rapidly if the 

 sky be clear, the air io contact with grass 

 a-nd other substances which are cooled by 

 this radiatiofi, will deposit its moist?ire m a 

 manner analogous to that of the deposition 

 of water on a surface of a metallic vessel 

 containing a cold liqtiid. Although the at- 

 mosphere may contain the same amouet of 

 vapor, yet the quantity of dew deposited 

 disriog differerit nights, in different places, 

 aod on difierent substafnces, is very different. 

 It is evident that, all things beii)g equal, it 

 must depend upon the -quantity of moisture, 

 since if the air were dry no deposition 

 could take place ; and, indeed, it has been 

 remarked that on some parts of the plains 

 west of the I\Iississippi dew is oever observ- 

 ed. It must also depend upon the clearness 

 of the sky; for, if the heavens be covered 

 with a cloud the radiant heat from the earth 

 will laot pass off into celestial space, but will 

 be partly absorbed by the cloud and radiated 

 back to the earth. This is not a mere hy- 

 pothesis, but has been proved by direct ex- 

 periment. The author of this article, while 

 at Princeton, some years ago, placed a ther- 

 mo-electric apparatus in the bottom of a 

 tube provided with a conical reflector, and 



