- Email: [email protected]
Physics of color centers
BOOK REVIEWS
p o p u l a r scientific m a g a z i n e such as Sky and Telescope. While its title claims otherwise, t h e b o o k presents t h e m a t e r i a l s o m e w h a t m o r e as a textbook would than a handbook: although t h e r e is some t a b u l a t i o n of data, absolutely no references are g i v e n and t h e d a t a which are t a b u l a t e d seem of limited usefulness. T h e book is n o t a true t e x t , however, since its a p p r o a c h is d o g m a t i c r a t h e r t h a n t u t o r i a l ; t h e e q u a t i o n s t h a t are p r e s e n t e d are only sketchily discussed a n d rarely derived. The book consists of t e n c h a p t e r s w r i t t e n b y a t o t a l of eight authors, including t h e two editors. T h e first two chapters describe t h e characteristics of the universe, t h e solar system, and t h e n e a r - E a r t h e n v i r o n m e n t ; t h e y each c o n t a i n n u m e r o u s errors a n d are p o o r l y written. T h e middle of t h e book has four chapters on space flight mechanics including orbital m e c h a n ics, navigation, and a t t i t u d e c o n t r o l ; these c h a p t e r s arc s o m e w h a t q u a l i t a t i v e b u t generally accurate. A f t e r a short general section on m a n in space, t h e r e are t w o c h a p t e r s which briefly discuss early (pre-1966) Soviet a n d A m e r i c a n spacecraft, their missions, a n d their propulsion systems. l~lumerous illustrations of t h e spacecraft and the a s t r o n a u t s are presented, as are listings of t h e orbital characteristics of m o s t Russian a n d m a n y A m e r i c a n space flights. Those prospective readers who seek to k n o w m o r e a b o u t t h e Russian space p r o g r a m m a y be disappointed, h o w e v e r ; t h e Russian p r o g r a m seems to be m e n t i o n e d s o m e w h a t less f r e q u e n t l y in the whole book t h a n is t h e A m e r i c a n program. T h e Handbook o] Astronautics ends b y discussing current and future spacecraft applications. U n h a p p i l y , this last c h a p t e r contains some p r o p a g a n d a ; while claiming t h a t " t h e Soviet U n i o n ... pursue[s] a peaceful course of a c t i o n , " t h e book emphasizes t h e m i l i t a r y applications of space being m a d e b y t h e U.S.A. T h e A m e r i c a n geodetic satellites, w e a t h e r satellites, Gemini series, et al. are all described as m i l i t a r y vehicles. The translation reads s m o o t h l y a n d m o s t technical words are t r a n s l a t e d correctly, w i t h a few exceptions ( " a v e r a g e a n o m a l y " is used in place of " m e a n a n o m a l y " a n d "peripheral v e l o c i t y " r a t h e r t h a n "surface v e l o c i t y " ) . T h e r e are a few unusual definitions as well: " t r a n s v e r s e l o a d " is used for t h e inverse of t h e spacecraft cross-sectional area per u n i t m a s s ; and w h a t is an " a i r - b r e a t h i n g e n g i n e " ? Is it dangerous? T h e r e are v e r y few t y p o g r a p h i c a l errors and t h e illustrations h a v e been r e p r o d u c e d a c c u r a t e l y f r o m illustrations of originally poor quality. A brief index has been a d d e d in translation.
141
I n s u m m a r y , there are few reasons for a s t u d e n t or researcher to o b t a i n Handbook of Astronautics e x c e p t t h a t it is inexpensive. Jos~.PH A. B~mNs
Center for Radiophysics and Space Research and Dept. of Mechanics Cornell University Ithaca, New York 14850 P h y s i c s o f Color Centers. W. B E ~ FOWLER. A c a d e m i c Press, N e w Y o r k & London, 1968. xiii + 655 pp. Price $24.50.
O v e r 150 years ago W o l l a s t o n a n d Berzelius observed in certain minerals w h a t is now called thermolumineseence. Over t h e years o t h e r p h e n o m e n a related to the so-called p o i n t defects in all kinds of crystals were discovered and their relationship to irradiation effects p r o d u c e d either b y n a t u r a l r a d i o a c t i v i t y or b y progressively more controllable radiation sources such as X-rays, y-rays, protons, neutrons, a n d electrons established. As a result p o i n t defects and, in particular, color centers b e c a m e a highly sophisticated a n d rich field of e x p e r i m e n t a l a n d theoretical investigations in solid state physics. This r e l a t i v e l y recent d e v e l o p m e n t is v e r y well d o c u m e n t e d in " P h y s i c s of Color C e n t e r s " edited b y W. Beall Fowler. T h e b o o k contains eight chapters and two appendices b y various authors, all of t h e m well k n o w n experts in t h e field. The first two chapters give a general t r e a t m e n t of electronic states a n d excitations in perfect and imperfect crystals. T h e t h i r d one is d e v o t e d to a special class of centers, t h e socalled FA centers, while t h e f o u r t h describes t h e application of laser t e c h n i q u e s in color center studies. I n t h e n e x t three chapters v a r i o u s aspects of the d y n a m i c coupling b e t w e e n t h e color centers a n d t h e surrounding crystal such as zero-phonon transitions and localized modes, are discussed. T h e last c h a p t e r covers t h e t h e o r y and t h e results of E S R and E N D O R resonance m e t h o d s as applied to color center research. One a p p e n d i x lists t h e principal bulk characteristics of alkali halides, the second gives optical p a r a m e t e r s and absorption bands of various centers. T h e general level of t h e book is v e r y high and t h e theoretical chapters assume a good knowledge of q u a n t u m mechanical m e t h o d s in solid state physics. Diagrams, references, a n d subject index are v e r y good. Since Icarus is d e v o t e d to solar s y s t e m studies one m a y pose t h e question w h e t h e r color center physics will e v e n t u a l l y find application in this area. T h e present d a y explosion of i n f o r m a t i o n
142
BOOK REVIEWS
a b o u t p l a n e t s a n d especially a b o u t o u r Moon m a k e a n a f f i r m a t i v e a n s w e r plausible. T h e m a i n r e a s o n for t h i s e x p e c t a t i o n is t h e fact t h a t t h e solid b o d i e s o f t h e solar s y s t e m are constantly exposed to powerful particulate and electromagnetic radiations which undoubtedly p r o d u c e all k i n d s o f p o i n t defects in t h e solids, especially in t h o s e o n t h e surface. W h i l e a n explicit a p p l i c a t i o n of color c e n t e r p h y s i c s h a s n o t gone b e y o n d a few q u a l i t a t i v e s p e c u l a t i o n s c o n c e r n i n g t h e c o l o r a t i o n of t h e M o o n a n d Mars, t h e r e h a s b e e n c o n s i d e r a b l e use of t h e b r o a d e r c o n c e p t s of p o i n t defects in q u a n t i t a t i v e t h e o r i e s of coherency and luminescence of the lunar surface. A n e x t e n s i o n of t h e p r e s e n t e x p e r i m e n t a l a n d t h e o r e t i c a l color c e n t e r p h y s i c s t o c r y s t a l s m o r e c o m p l i c a t e d t h a n alkali halides a n d in p a r t i c u l a r t o s u c h m i n e r a l s as b a s a l t , olivine, l i m o n i t e , etc., m a y lead t o i m p o r t a n t developm e n t s in p l a n e t a r y physics. R . SMOLUCHOWSKI
School of Engineering and Applied Science Princeton University Princeton, New Jersey 08540 Polar and Magnetospheric Substerms. SYUNICHI AKASOFU. D. R e i d e l P u b l i s h i n g Co., Dordrecht, Holland; Springer-Verlag New York I n c . , N e w Y o r k , 1968. xviii + 280 pp. P r i c e $16.50. W h i l e t h e s h e e r b e a u t y of t h e a u r o r a borealis h a s s t i m u l a t e d c u r i o s i t y a n d scientific s t u d y for centuries, most of the relevant information on a u r o r a a n d a s s o c i a t e d p h e n o m e n a (such as t h e E a r t h ' s r a d i a t i o n belts) h a s b e e n o b t a i n e d in t h e p a s t d e c a d e or so. T h i s explosive increase in k n o w l e d g e arose f r o m a c o m b i n a t i o n of t h e e s t a b l i s h m e n t of large n u m b e r s of g r o u n d - b a s e d o b s e r v i n g s t a t i o n s for t h e I n t e r n a t i o n a l Geop h y s i c a l Y e a r a n d t h e a d v e n t of satellites a n d t h e space age. O n l y n o w is t h e v a s t q u a n t i t y o f d a t a b e i n g classified, c a t a l o g u e d , a n d d i g e s t e d so t h a t t h e " t y p i c a l e v e n t " c a n b e s e p a r a t e d from the "atypical event." The book "Polar and M a g n e t o s p h e r i c S u b s t e r n ~ s " b y S-I. A k a s o f u r e p r e s e n t s a n o u t s t a n d i n g l a n d m a r k in t h i s process. I t is r a r e i n d e e d in a r a p i d l y d e v e l o p i n g field to find a b o o k w h i c h is as u p - t o - d a t e as a n y m u l t i p l y - a u t h o r e d collection o f r e v i e w p a p e r s while p r e s e n t i n g t h e c o h e r e n t o v e r v i e w o f single authorship. A p r i n c i p l e p u r p o s e of t h e b o o k is t o p o i n t o u t t h e essential u n i t y of t h e s t u d y of t h e field. A k a s o f u n o t e s in t h e i n t r o d u c t o r y c h a p t e r t h a t in o b s e r v a t i o n s of m a n y different u p p e r -
atmosphere auroral-zone phenomena, disturba n c e s or e v e n t s h a v e a c h a r a c t e r i s t i c d u r a t i o n o f 1 t o 3 hours, a n d in e a c h case t h e " t y p i c a l e v e n t " is r e f e r r e d t o as a " s u b s t o r m . " S u b s e q u e n t c h a p t e r s deal w i t h t h e a u r o r a l s u b s t o r m , t h e m a g n e t i c s u b s t o r m , ionospheric s u b s t o r m , X - r a y s u b s t o r m , p r o t o n a u r o r a s u b s t o r m , V L F emission s u b s t e r m , a n d m i c r o p u l s a t i o n s u b s t o r m . F o r e a c h of t h e s e p h e n o m e n a , t h e n a t u r e a n d d i s t r i b u t i o n of t h e d i s t u r b a n c e o v e r t h e p o l a r region are g i v e n as a f u n c t i o n of t i m e a f t e r t h e s u b s t o r m onset. C h a p t e r 9 r e l a t e s s a t e l l i t e observations to those made at ground stations. T h e t e n d e n c y t o a c c e n t u a t e differences in t h e morphology of the various phenomena inherent in t h e o r g a n i z a t i o n of c h a p t e r s u s e d in t h e b o o k is c o u n t e r a c t e d in p a r t b y C h a p t e r 9, w h e r e t h e i n t e r r e l a t i o n s h i p o f t h e satellite d a t a a n d t h e v a r i o u s g r o u n d - b a s e d o b s e r v a t i o n s is m a d e a p p a r e n t . T h e essential u n i t y o f t h e o b s e r v a t i o n s is also s t r e s s e d in t h e final c h a p t e r w h i c h i n c l u d e s (noncritical) o u t l i n e s of t h e v a r i o u s t h e o r i e s proposed to date. T h e one serious omission f r o m t h e b o o k is a reference t o t h e w h i s t l e r o b s e r v a t i o n s o f D. L . C a r p e n t e r a n d K . S t o n e (Direct d e t e c t i o n b y a w h i s t l e r m e t h o d of a m a g n e t o s p h e r i c electric field a s s o c i a t e d w i t h a p o l a r s u b s t o r m , Planetary Space Sci. 15, 395-397, 1967) w h o f o u n d e v i d e n c e o f large-scale q u a s i - s t a t i c electric fields d e e p within the magnetosphere whose onset preceded t h e a p p a r e n t s u b s t o r m o n s e t (as d e t e r m i n e d f r o m m a g n e t i c o b s e r v a t i o n s ) b y some 10 or 20 m i n u t e s . T h e s e electric fields p r o v i d e s t r o n g evidence that magnetospheric convection plays a m a j o r role in t h e p r o d u c t i o n of s u b s t o r m s . T h e c o n t e n t of t h e b o o k m i r r o r s t h e field as a whole, p a y i n g (justifiably) m u c h m o r e a t t e n t i o n to experimental observation than to prevalent theories. T h i s b o o k will b e a n i n v a l u a b l e i n t r o d u c t i o n for s t u d e n t s n e w t o t h e field as well as a n essential reference for t h e old b a n d s . NEIL BRICE
Center.for Radiophysies and Space Research Cornell University Ithaca, New York 14850 Earth Photographs from Gemini III, IV, and V. N A S A SP-123. N A S A Office o f T e c h n o l o g y U t i l i z a t i o n , W a s h i n g t o n D.C. 1967. ix + 266 p p . Price $7.00. "Earth Photographs from Gemini III, IV, a n d V , " N A S A SP-129, originally p u b l i s h e d in 1967, is a v a l u a b l e collection of 224 color r e p r o d u c t i o n s o f t e r r a i n a n d cloud p h o t o g r a p h s .
p o p u l a r scientific m a g a z i n e such as Sky and Telescope. While its title claims otherwise, t h e b o o k presents t h e m a t e r i a l s o m e w h a t m o r e as a textbook would than a handbook: although t h e r e is some t a b u l a t i o n of data, absolutely no references are g i v e n and t h e d a t a which are t a b u l a t e d seem of limited usefulness. T h e book is n o t a true t e x t , however, since its a p p r o a c h is d o g m a t i c r a t h e r t h a n t u t o r i a l ; t h e e q u a t i o n s t h a t are p r e s e n t e d are only sketchily discussed a n d rarely derived. The book consists of t e n c h a p t e r s w r i t t e n b y a t o t a l of eight authors, including t h e two editors. T h e first two chapters describe t h e characteristics of the universe, t h e solar system, and t h e n e a r - E a r t h e n v i r o n m e n t ; t h e y each c o n t a i n n u m e r o u s errors a n d are p o o r l y written. T h e middle of t h e book has four chapters on space flight mechanics including orbital m e c h a n ics, navigation, and a t t i t u d e c o n t r o l ; these c h a p t e r s arc s o m e w h a t q u a l i t a t i v e b u t generally accurate. A f t e r a short general section on m a n in space, t h e r e are t w o c h a p t e r s which briefly discuss early (pre-1966) Soviet a n d A m e r i c a n spacecraft, their missions, a n d their propulsion systems. l~lumerous illustrations of t h e spacecraft and the a s t r o n a u t s are presented, as are listings of t h e orbital characteristics of m o s t Russian a n d m a n y A m e r i c a n space flights. Those prospective readers who seek to k n o w m o r e a b o u t t h e Russian space p r o g r a m m a y be disappointed, h o w e v e r ; t h e Russian p r o g r a m seems to be m e n t i o n e d s o m e w h a t less f r e q u e n t l y in the whole book t h a n is t h e A m e r i c a n program. T h e Handbook o] Astronautics ends b y discussing current and future spacecraft applications. U n h a p p i l y , this last c h a p t e r contains some p r o p a g a n d a ; while claiming t h a t " t h e Soviet U n i o n ... pursue[s] a peaceful course of a c t i o n , " t h e book emphasizes t h e m i l i t a r y applications of space being m a d e b y t h e U.S.A. T h e A m e r i c a n geodetic satellites, w e a t h e r satellites, Gemini series, et al. are all described as m i l i t a r y vehicles. The translation reads s m o o t h l y a n d m o s t technical words are t r a n s l a t e d correctly, w i t h a few exceptions ( " a v e r a g e a n o m a l y " is used in place of " m e a n a n o m a l y " a n d "peripheral v e l o c i t y " r a t h e r t h a n "surface v e l o c i t y " ) . T h e r e are a few unusual definitions as well: " t r a n s v e r s e l o a d " is used for t h e inverse of t h e spacecraft cross-sectional area per u n i t m a s s ; and w h a t is an " a i r - b r e a t h i n g e n g i n e " ? Is it dangerous? T h e r e are v e r y few t y p o g r a p h i c a l errors and t h e illustrations h a v e been r e p r o d u c e d a c c u r a t e l y f r o m illustrations of originally poor quality. A brief index has been a d d e d in translation.
141
I n s u m m a r y , there are few reasons for a s t u d e n t or researcher to o b t a i n Handbook of Astronautics e x c e p t t h a t it is inexpensive. Jos~.PH A. B~mNs
Center for Radiophysics and Space Research and Dept. of Mechanics Cornell University Ithaca, New York 14850 P h y s i c s o f Color Centers. W. B E ~ FOWLER. A c a d e m i c Press, N e w Y o r k & London, 1968. xiii + 655 pp. Price $24.50.
O v e r 150 years ago W o l l a s t o n a n d Berzelius observed in certain minerals w h a t is now called thermolumineseence. Over t h e years o t h e r p h e n o m e n a related to the so-called p o i n t defects in all kinds of crystals were discovered and their relationship to irradiation effects p r o d u c e d either b y n a t u r a l r a d i o a c t i v i t y or b y progressively more controllable radiation sources such as X-rays, y-rays, protons, neutrons, a n d electrons established. As a result p o i n t defects and, in particular, color centers b e c a m e a highly sophisticated a n d rich field of e x p e r i m e n t a l a n d theoretical investigations in solid state physics. This r e l a t i v e l y recent d e v e l o p m e n t is v e r y well d o c u m e n t e d in " P h y s i c s of Color C e n t e r s " edited b y W. Beall Fowler. T h e b o o k contains eight chapters and two appendices b y various authors, all of t h e m well k n o w n experts in t h e field. The first two chapters give a general t r e a t m e n t of electronic states a n d excitations in perfect and imperfect crystals. T h e t h i r d one is d e v o t e d to a special class of centers, t h e socalled FA centers, while t h e f o u r t h describes t h e application of laser t e c h n i q u e s in color center studies. I n t h e n e x t three chapters v a r i o u s aspects of the d y n a m i c coupling b e t w e e n t h e color centers a n d t h e surrounding crystal such as zero-phonon transitions and localized modes, are discussed. T h e last c h a p t e r covers t h e t h e o r y and t h e results of E S R and E N D O R resonance m e t h o d s as applied to color center research. One a p p e n d i x lists t h e principal bulk characteristics of alkali halides, the second gives optical p a r a m e t e r s and absorption bands of various centers. T h e general level of t h e book is v e r y high and t h e theoretical chapters assume a good knowledge of q u a n t u m mechanical m e t h o d s in solid state physics. Diagrams, references, a n d subject index are v e r y good. Since Icarus is d e v o t e d to solar s y s t e m studies one m a y pose t h e question w h e t h e r color center physics will e v e n t u a l l y find application in this area. T h e present d a y explosion of i n f o r m a t i o n
142
BOOK REVIEWS
a b o u t p l a n e t s a n d especially a b o u t o u r Moon m a k e a n a f f i r m a t i v e a n s w e r plausible. T h e m a i n r e a s o n for t h i s e x p e c t a t i o n is t h e fact t h a t t h e solid b o d i e s o f t h e solar s y s t e m are constantly exposed to powerful particulate and electromagnetic radiations which undoubtedly p r o d u c e all k i n d s o f p o i n t defects in t h e solids, especially in t h o s e o n t h e surface. W h i l e a n explicit a p p l i c a t i o n of color c e n t e r p h y s i c s h a s n o t gone b e y o n d a few q u a l i t a t i v e s p e c u l a t i o n s c o n c e r n i n g t h e c o l o r a t i o n of t h e M o o n a n d Mars, t h e r e h a s b e e n c o n s i d e r a b l e use of t h e b r o a d e r c o n c e p t s of p o i n t defects in q u a n t i t a t i v e t h e o r i e s of coherency and luminescence of the lunar surface. A n e x t e n s i o n of t h e p r e s e n t e x p e r i m e n t a l a n d t h e o r e t i c a l color c e n t e r p h y s i c s t o c r y s t a l s m o r e c o m p l i c a t e d t h a n alkali halides a n d in p a r t i c u l a r t o s u c h m i n e r a l s as b a s a l t , olivine, l i m o n i t e , etc., m a y lead t o i m p o r t a n t developm e n t s in p l a n e t a r y physics. R . SMOLUCHOWSKI
School of Engineering and Applied Science Princeton University Princeton, New Jersey 08540 Polar and Magnetospheric Substerms. SYUNICHI AKASOFU. D. R e i d e l P u b l i s h i n g Co., Dordrecht, Holland; Springer-Verlag New York I n c . , N e w Y o r k , 1968. xviii + 280 pp. P r i c e $16.50. W h i l e t h e s h e e r b e a u t y of t h e a u r o r a borealis h a s s t i m u l a t e d c u r i o s i t y a n d scientific s t u d y for centuries, most of the relevant information on a u r o r a a n d a s s o c i a t e d p h e n o m e n a (such as t h e E a r t h ' s r a d i a t i o n belts) h a s b e e n o b t a i n e d in t h e p a s t d e c a d e or so. T h i s explosive increase in k n o w l e d g e arose f r o m a c o m b i n a t i o n of t h e e s t a b l i s h m e n t of large n u m b e r s of g r o u n d - b a s e d o b s e r v i n g s t a t i o n s for t h e I n t e r n a t i o n a l Geop h y s i c a l Y e a r a n d t h e a d v e n t of satellites a n d t h e space age. O n l y n o w is t h e v a s t q u a n t i t y o f d a t a b e i n g classified, c a t a l o g u e d , a n d d i g e s t e d so t h a t t h e " t y p i c a l e v e n t " c a n b e s e p a r a t e d from the "atypical event." The book "Polar and M a g n e t o s p h e r i c S u b s t e r n ~ s " b y S-I. A k a s o f u r e p r e s e n t s a n o u t s t a n d i n g l a n d m a r k in t h i s process. I t is r a r e i n d e e d in a r a p i d l y d e v e l o p i n g field to find a b o o k w h i c h is as u p - t o - d a t e as a n y m u l t i p l y - a u t h o r e d collection o f r e v i e w p a p e r s while p r e s e n t i n g t h e c o h e r e n t o v e r v i e w o f single authorship. A p r i n c i p l e p u r p o s e of t h e b o o k is t o p o i n t o u t t h e essential u n i t y of t h e s t u d y of t h e field. A k a s o f u n o t e s in t h e i n t r o d u c t o r y c h a p t e r t h a t in o b s e r v a t i o n s of m a n y different u p p e r -
atmosphere auroral-zone phenomena, disturba n c e s or e v e n t s h a v e a c h a r a c t e r i s t i c d u r a t i o n o f 1 t o 3 hours, a n d in e a c h case t h e " t y p i c a l e v e n t " is r e f e r r e d t o as a " s u b s t o r m . " S u b s e q u e n t c h a p t e r s deal w i t h t h e a u r o r a l s u b s t o r m , t h e m a g n e t i c s u b s t o r m , ionospheric s u b s t o r m , X - r a y s u b s t o r m , p r o t o n a u r o r a s u b s t o r m , V L F emission s u b s t e r m , a n d m i c r o p u l s a t i o n s u b s t o r m . F o r e a c h of t h e s e p h e n o m e n a , t h e n a t u r e a n d d i s t r i b u t i o n of t h e d i s t u r b a n c e o v e r t h e p o l a r region are g i v e n as a f u n c t i o n of t i m e a f t e r t h e s u b s t o r m onset. C h a p t e r 9 r e l a t e s s a t e l l i t e observations to those made at ground stations. T h e t e n d e n c y t o a c c e n t u a t e differences in t h e morphology of the various phenomena inherent in t h e o r g a n i z a t i o n of c h a p t e r s u s e d in t h e b o o k is c o u n t e r a c t e d in p a r t b y C h a p t e r 9, w h e r e t h e i n t e r r e l a t i o n s h i p o f t h e satellite d a t a a n d t h e v a r i o u s g r o u n d - b a s e d o b s e r v a t i o n s is m a d e a p p a r e n t . T h e essential u n i t y o f t h e o b s e r v a t i o n s is also s t r e s s e d in t h e final c h a p t e r w h i c h i n c l u d e s (noncritical) o u t l i n e s of t h e v a r i o u s t h e o r i e s proposed to date. T h e one serious omission f r o m t h e b o o k is a reference t o t h e w h i s t l e r o b s e r v a t i o n s o f D. L . C a r p e n t e r a n d K . S t o n e (Direct d e t e c t i o n b y a w h i s t l e r m e t h o d of a m a g n e t o s p h e r i c electric field a s s o c i a t e d w i t h a p o l a r s u b s t o r m , Planetary Space Sci. 15, 395-397, 1967) w h o f o u n d e v i d e n c e o f large-scale q u a s i - s t a t i c electric fields d e e p within the magnetosphere whose onset preceded t h e a p p a r e n t s u b s t o r m o n s e t (as d e t e r m i n e d f r o m m a g n e t i c o b s e r v a t i o n s ) b y some 10 or 20 m i n u t e s . T h e s e electric fields p r o v i d e s t r o n g evidence that magnetospheric convection plays a m a j o r role in t h e p r o d u c t i o n of s u b s t o r m s . T h e c o n t e n t of t h e b o o k m i r r o r s t h e field as a whole, p a y i n g (justifiably) m u c h m o r e a t t e n t i o n to experimental observation than to prevalent theories. T h i s b o o k will b e a n i n v a l u a b l e i n t r o d u c t i o n for s t u d e n t s n e w t o t h e field as well as a n essential reference for t h e old b a n d s . NEIL BRICE
Center.for Radiophysies and Space Research Cornell University Ithaca, New York 14850 Earth Photographs from Gemini III, IV, and V. N A S A SP-123. N A S A Office o f T e c h n o l o g y U t i l i z a t i o n , W a s h i n g t o n D.C. 1967. ix + 266 p p . Price $7.00. "Earth Photographs from Gemini III, IV, a n d V , " N A S A SP-129, originally p u b l i s h e d in 1967, is a v a l u a b l e collection of 224 color r e p r o d u c t i o n s o f t e r r a i n a n d cloud p h o t o g r a p h s .