446 T. T. QUIRKE 



At a height of 60 miles above the earth the air is extremely 

 thin, indicating that the meteorite entered the atmosphere at a 

 very high velocity, otherwise it would not have developed enough 

 friction with the air to cause combustion. The meteorite fell 

 near latitude 46° 30', in June, at approximately 10 p.m., at an 

 angle of 27° to the surface, going northward, from which data it 

 follows that the meteorite was falling toward the sun when it was 

 intercepted by the earth. Falling at an angle of about 90° to the 

 course of the earth, the meteorite entered the earth's atmosphere 

 at neither the highest nor the lowest velocity possible relative to 

 the earth. In other words it fell neither directly opposite to the 

 earth's flight, the condition of maximum velocity, nor did it 

 catch up with the earth, a condition of minimum velocity. How- 

 ever, a meteorite falling toward the sun at the distance of the 

 earth's orbit commonly has a velocity of 25 miles per second. By 

 the earth's attraction the velocity might have been increased to 

 30 miles per second. It seems a conservative estimate to call the 

 velocity of the meteorite when it entered our atmosphere about 30 

 miles per second. 



The general unbroken condition of most of the examples of 

 the fall, in spite of their brittle nature, indicates that the meteorite 

 struck the earth's surface at a relatively low velocity. It is not 

 clear why a meteorite should become incandescent in a very 

 tenuous atmosphere, 60 miles above- the earth, and then why 

 its broken fragments after disruption in much denser air should 

 not burn, unless the velocity is decreased enormously during its 

 passage through the air. The meteorite must have passed through 

 at least 117 miles of air from the time it commenced to burn until 

 it reached the earth. This thickness of atmosphere appears to 

 have offered enough obstruction to the passage of the meteorite 

 to reduce the velocity from probably about 30 miles per second to 

 something much less. All this, of course, is quite in accordance 

 with commonly accepted notions as to the ge'neral behavior of 

 meteorites. If anything, the height at which the meteorite is 

 estimated to have commenced to burn is somewhat low for the 

 velocity postulated. However, the general probability of the con- 

 clusions reflects most creditably upon the accuracy of the observa- 

 tions of both Mr. Loran and Mr. St. Marie. 



