An earlier analysis of Prairie Network fireball trajectory data by the authors failed to discriminate between the varieties of meteoric materials that are thought to be present. The Lost City meteorite event offers a new calibration of the fireball data and prompts a new analysis intended to distinguish between ordinary chondritic meteorites and the more fragile early type carbonaceous chondrites. The carbonaceous material is expected to ablate more readily and thus to have shorter trajectories or higher end heights. Observational error and the natural dispersion in the structures produce severe smoothing effects, and the end height diagnostic is, in itself, not entirely convincing. However, after making a tentative division of the data, one can discern differences in orbits and beginning heights among the three end height groups. These are consistent with our expectation of the behavior of chondritic stones (group I), weak carbonaceouS chondrites (group II), and still more fragile cometary material (group III). We conclude that if the carbonaceous material occurs in reasonable abundance among the fireballs, it has been properly identified by this analysis. If either of the above conditions does not obtain in fact then there is little hope of discriminating between meteorite classes in the fireball data.Third, we assume that there is some direct 6257 6258 Ceplecha and McCrosky' Fireball End Heights relationship between a meteoroid's strength, asmeasured by its fragmentation or ablation rate, and its density. We will later show data that can be construed to support this view, but the best arguments in its favor will be one's everyday experience with a variety of, materials, which, for some, include the various chondritic meteorites discussed previously. Anearly qualitative result of the analysis of the PN data was the observation that there could be very great differences in end heights (end of visible trajectory) for fireballs of comparable brightness, velocity, and trajectory angle. The ratio of the amount of atmosphere penetrated can exceed 100:1. The meteor • end +0.6 -+0.4 -A ,,,, +0.2v oß -0.2 --0.4 --0.6 -ß ß ß ß ß ß I i ß ß ß ß / ß ß ! ß i i -4.4 -4.8 PE

S m i t h s o n i a n A s t r o p h y s i c a l O b s e r v a t o r y and H a r v a r d College O b s e r v a t o r y , C a m b r i d g e , M a s s a c h u s e t t s 021 38T h e L o s t City m e t e o r i t e was photographed i n flight and r e c o v e r e d by t h e P r a i r i e Network. F o u r f r a g m e n t s totaling 17 kg have been found. ALI analysis of a t h i r d m e t e o r , No, 405 0 3 , is p r e s e n t e d a s a counterexample t o the above a r g u m e n t 'This mete o r of 1 00 t i m e s the intensity of L o s t City r e a c h e d m a x i m u m light and then w a s extinguished nearly instantaneously. We recognize t h a t t h i s i s a different kind of m e t e o r o i d but have no s a t i s f a c t o r y explanation f o r i t s behavior. P h o t o m e t r i c and t r a j e c t o r y d a t a f o r the L o s t City m e t e o r and f o r a subs e q u e n t m e t e o r (No. 4061 7) with s i m i l a r flight c h a r a c t e r i s t i c s a r e u s e d t o e s t a b l i s h a p r e l i m i n a r y c a l i b r a t i o n of the m a s s s c a l e of o t h e r f i r e b a l l s . T h e r e i s e x c e l l e n t a g r e e m e n t between t h e p h o t o m e t r i c m a s s e s d e r i v e d f r o m t h e m o s t r e c e n t d e t e r m i n a t i o n of t h e luminous efficiency of the m e t e o r i c p r o c e s s , and the dynamic m a s s e s d e t e r m i n e d f r o m the t r a j e c t o r y and the s h a p e of the r e c o v e r e d m e t e o r i t e . It i s unlikely t h a t p h o t o m e t r i c m a s s e s a r e o v e r e s t i m a t e d by a s m u c h a s a f a c t o r ofT h e o r b i t s of t h e s e m e t e o r s a r e s i m i l a r t o t h o s e of m o s t o t h e r f i r e b a l l s . . T H E LOST CITY M E T E O RT h e L o s t City m e t e o r o c c u r r e d o v e r n o r t h e a s t e r n Oklahoma a t 2014 CST on J a n u a r y 3, 1970. T h e f i r e b a l l a t m a x i m u m light was c o m p a r a b l e i n b r i g h tn e s s t o the full moon. It w a s widely o b s e r v e d . Sonic booms w e r e r e p o r t e d 2 to have b e e n h e a r d o v e r a n a r e a of about 1000 k m between T u l s a and Tahlequah.2 W e l l -c o n f i r m e d r e p o r t s of t h e audio event c o v e r a n a r e a of a t l e a s t 300 k m , T h e m e t e o r was photographed f r o m f o u r P r a i r i e Network s t a t i o n s i n Hominy and Woodward, Oklahoma, and P l e a s a n t o n and G a r d e n City, K a n s a s D u r i n g t h e l a s t 1. 5 s e c of t h e t r a i l , t h r e e s e p a r a t e f r a g m e n t s a r e visible on t h e Hominy photograph. The o t h e r , m o r e distant s t a t i o n s e i t h e r do not show t h e end portion of t h e t r a i l o r have insvlficient resolution, The f a i n t e s t t r a i l (111) i s well separated on the photograph frorn the brightest (I) i o r the l.ast I s e c of its trajectory-and can be m e a s u r e d a s a s e p a r a t e object. At m its end h e i g h t ( 2 4 icrulj, the veiccity i s 4 lirnjsec, L he t r a i l of irrterrnediate brightness (11) i ...

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This series, Smithsonian Contributions to Astrophysics, was inaugurated in 1956 to provide a proper communication for the results of research conducted at the Astrophysical Observatory of the Smithsonian Institution. Its purpose is the "increase and diffusion of knowledge" in the field of astrophysics, with particular emphasis on problems of the sun, the earth, and the solar system. Its pages are open to a limited number of papers by other investigators with whom we have common interests. Another series is Annals of the Astrophysical Observatory. It was started in 1900 by the Observatory's first director, Samuel P. Langley, and has been published about every 10 years since that date. These quarto volumes, some of which are still available, record the history of the Observatory's researches and activities. Many technical papers and volumes emanating from the Astrophysical Observatory have appeared in the Smithsonian Miscellaneous Collections. Among these are Smithsonian Physical Tables, Smithsonian Meteorological Tables, and World Weather Records.

Smithsonian I n s t i t u t i o n Astrophysical ObservatoryCambridge, Massachusetts 02138Composite Photograph taken with Prairie Network Meteor Cameras.The very b r i g h t object at r i g h t center is a short, b r i g h t meteor photographed at t h e Carroll, Iowa, s t a t i o n . S t a r t r a i l s d i s p l a y points of increased brightness each 10 minutes. These f i d u c i a l points are used i n the d a t a reduction procedure.The long meteor, centered on the f i l m , w a s photographed through an overcast sky at t h e Reliance, 6011th Dakota s t a t i o n and has been superimposed on t h i s picture t o i l l u s t r a t e t h e e f f e c t s produced by the coding s h u t t e r .The dashed l i n e at t h e lower r i g h t i s a passing-car on t h e horizon.