128 .Appendix. 



order to prove the identity of this matter, a comparison was 

 made with a specimen of Peles' hair from the Sandwich Island 

 volcano. This hair or fine spun glass is composed mainly of 

 silica and silicates, and is produced from lava in a stafe of ex- 

 treme fluidity, by the force of volcanic action, and the force of 

 the wind, drawing out the melted matter into glass threads and 

 hairs, sometimes smooth and sometimes crisped or curled. This 

 comparison, however, was somewhat unsatisfactory, as far as 

 proving a perfect identity was concerned. Both substances pre- 

 sented very much the same appearance, with the exception of the 

 earthy matter, which was not present in any quantity in the val- 

 canic matter used for comparison. Upon mixing it with earthy 

 matter, the two substances resembled each other very much in 

 their nature, both presenting the same tubular appearance and 

 general appearance. In fact, they were almost identical. 



It was suggested to compare the sediment with some of the 

 dust which, blown up from the streets, is deposited on the roofs 

 of buildings. To this end, I collected some of the dust from a 

 clean place on the roof of one of the stores on Main street, and 

 subjected it to microscopic examination. It was made up prin- 

 cipally of silica colored with organic and earthy matter, showing 

 plainly the presence of woody fibre, but presenting an appearance 

 quite unlike the sediment in question. Its appearance under the 

 microscope, therefore, according to our eyes, did not prove its 

 identity. It is certainly quite impossible that this substance 

 could have had its origin anywhere in Michigan. It came from 

 some point south-west, and must have been carried across Lake 

 Michigan. The distance across the lake at that point is prob- 

 ably between sixty and one hundred miles. From whatever 

 source it may have originated, then, it doubtless was carried by 

 the upper current, which, according to Dr. Draper, is perpetually 

 blowing over most of the United States from the south-west, at 

 a height ranging above 7,000 feet, and at a velocity which is 

 very variable, but which increases with the height. 



On Monday last the dispatches reported the wind to be 

 blowing on the summit of Mount Washington at a velocity of 



