194 Examination of some Atmospheric Dust . [Feb, 



force, No. 1 ; N. E. No. 2 ; E. N. E. No. 3 ; N. E. and calm at daybreak ; what 

 was considered an ordinary mist was observed ; but those officers who walked 

 on shore at that time, noticed their shoes and trowsers dusty. This also I 

 experienced in the afternoon. After 8 A. M. dust was perceptible on the 

 guns, on the upper works, and other polished surfaces on deck. I collected as 

 much as possible ; on gathering the dust on the finger, and holding it in the 

 rays of the sun, which consequently shone with half its brilliancy, the par- 

 ticles glittered, and the sand although impalpable between finger and thumb, 

 was gritty between the teeth. The sand passed the ship in light clouds, when 

 the light airs freshened ; it was something like smoke, but not of a blue co- 

 lour. At 2 P. M. I walked three miles into the country, the whole atmosphere 

 appeared to consist of a light brown dusty colored mist ; this was the uniform 

 appearance the whole day. The plants were covered. The sun set, appa- 

 rently more diminished in his diameter than on a frosty evening, and of a 

 pale white, sickly hue. At 10 P. M. I spread two large newspapers to catch 

 the sand ; they were kept spread until half past one media nocte • yet although 

 the sand descended and lay on the guns, none fell on the paper ; whether 

 from electric attraction or not I do not know. The stars, although the sky 

 was cloudless, Ursa Major in the zenith, were dimly visible. The moon three 

 days past her full was partially obscured, and cast a very faint shadow on my 

 hand ; at one media nocte the moon and stars resumed their usual appearance, 

 and at half-past one the Quarter Master observed " it was all over." The Baro- 

 meter 29. 88, from 30 inches.* If you breathed it through the mouth the sand 

 gritted between the teeth. The entire surface of this district is alluvial clay, 

 without pebble, or sand ; the nearest sand (coarse and shelly) is 12 miles 

 distant. It was said that the merchantman Denia fell in with this descent of 

 sand 308 miles from any land, in the direction of Loo-choo, and also pumice 

 stone was floating. As I did not see her log, I do not certify this fact. 



Yours sincerely, 

 J. Bellott. 

 D. J. Macgowan, Esq. M. D. Ningpo. 

 P. S. — I forward a little of the sand. 



I should premise that the entire weight of the minute specimen of 

 this dust forwarded to us did not exceed 1J grains, so that all the ex- 

 periments are performed with less than pin-head specimens, but che- 

 mists well know the accuracy with which these microscopic experiments 

 can demonstrate the presence or absence of certain elements, and from 



* So in MSS. I presume that what is meant is, that the Barometer fell to 29.88 from 

 30.00 ?-H. P. 



