394 Transactions. — Miscellaneous. 



In 1777, 17th June, about noon, Messier states he perceived an im- 

 mense number of black globules pass over the sun's disc. 

 In 1783 there was a dry fog, and many attributed it to volcanic 

 action, and it is well known that in February that year fearful 

 earthquakes in Calabria took place, followed by a long list of 

 volcanic eruptions in the world. 

 In 1831, there was an extraordinary dry fog, which excited public 

 attention throughout the world. It appeared on the coast of 

 Africa on the 3rd August ; at Odessa, on the 9th August ; in 

 South France, on the 10th August ; at Paris, on the 10th 

 August ; New York, on the 15th August ; Canton (China), at 

 the end of August. This fog was so thick that it was possible 

 to observe the sun all day with the naked eye, and without a 

 dark glass ; and in some places the sun could not be seen till it 

 was 15° or 20° high. At Algiers, United States, and Canton the 

 sun's disc appeared of an azure blue, or of a greenish colour. 

 Where the fog was dense, the smallest print could be read even 

 at midnight. 

 In 1873, of the dry fog which came on suddenly in June, it is 

 recorded that it extended from the northern coast of Africa, 

 over France, to Sweden, and over great part of North America, 

 and lasted more than a month. Travellers found it on the 

 summits of the Alps. Abundant rain in June and July, and 

 most violent winds did not dissipate it ; and in some places it 

 was so dense that the sun could not be seen until it had 

 attained an altitude of 12° ; and throughout the day-time it was 

 red and so dull that it might be looked at with the naked eye. 

 The fog diffused a disagreeable odour, and the humidity ranged 

 from 57 to 68, while in an ordinary fog it is 100. It had a 

 phosphorescent appearance, and the light at midnight was 

 compared to that of full moon. 

 Here was exhibited a diagram (pi. xix.), drawn correctly to a scale of 50 

 miles to an inch, showing the arc (of 15°) of a circle whose radius was 6 feet 7 

 inches, or a diameter of 13 feet 2 inches. The Himalayas were shown in their 

 correct proportion ; so was the smoke from Cotopaxi, estimated by Whymper, 

 while on Chimborazo, at 40,000 feet; he saw, at 5-45 a.m. of the 30th July, 

 1880, a dense column of smoke shot up straight into the atmosphere with 

 prodigious velocity, which in less than one minute had risen 20,000 feet 

 above the crater, giving the total height of 40,000 feet above sea-level. The 

 dust, he goes on to state, fell on Chimborazo after six hours, and he esti- 

 mated that each particle did not weigh the one-twenty-five-thousandth 

 (^rm^o) P ar ^ °f a grain, and the finest were still lighter. 



