106 AV. H. HOBBS- 



From the above it is clear that the Algoma iron belongs in the Char- 

 lotte group and is in many respects similar to Cohen's Charlotte type, 

 which fell in Charlotte, Dixon count3% Tennessee, in 1835. In all the 

 respects of coarseness of structure, proportions of the members of the 

 triad, varieties of kamacite and plessite, Neumann lines in kamacite, 

 fractures and their fillings, resistance to weathering, Reichenbach's la- 

 mellae, and their distribution in the network, it seems to correspond very 

 closely ; and one of Brezina and Cohen's plates * would fairly well rep- 

 resent the Algoma iron. In composition also there is but slight varia- 

 tion. Both irons are remarkably free from the elements not constituting 

 the triad. Algoma has 10.5 as against 8 per cent of nickel ; Charlotte 

 has .06 per cent of copper, which is not found in Algoma, and the latter 

 has .15 per cent of phosphorus, which is absent in the former. 



Theoretical — Manner of Flight 

 broadside attitude in translation 



There seems no reason to doubt that the Algoma meteorite moved 

 broadside on during its flight through the aerosphere, such being re- 

 quired by the well demonstrated laws of mechanics, albeit contrar\^ to 

 common notions. The principle referred to is illustrateel whenever a 

 card or disc falls by gravity against air resistance, and is in fact brought 

 out whenever a discoid body moves against air resistance from any ini- 

 tial attitude other than that which opposes the broadest surface to the 

 air pressure. In this attitude the air currents will wrap about the disc, 

 following the lines of least resistance. The body is urged forward by a 

 force (its momentum or gravity) whose resultant is applied at its center 

 of mass — its center of form. The resultant of the pressure of com- 

 pressed air is applied at a point some distance from the center of form 

 toward the end of the disc which is in advance. A couple is thus in- 

 duced tending to erect the body into a position normal to its line of 

 flight. If carried by this couple beyond the normal position, as it in- 

 evitably w'ould be, a reverse couple is set up, so that a pendular vibra- 

 tion w^ould precede for a longer or shorter interval its attitude of perfect 

 erectness normal to its path. 



Little attention seems to have been given to the manner of flight of 

 meteorites, probabl}^ because few investigators have had to deal with 

 definitely oriented bodies, and, with two recentl}" described exceptions, 

 none appear to have been mentioned which possess a flat form in any 

 degree approaching that of Algoma. As long ago as 1861, however, 



*I)ie Strnktiir and Zasammensetznng des Meteoriessens, plates xvii and xviii. 



