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A s e a r l y a s 1955, a low t e m p e r a t u r e phase t r a n s i t i o n had been p r o p o s e d for v a n a d i u m 1 and s i n c e that t i m e h o s t s of a n o m a l i e s have b e e n r e p o r t e d for the v a r i o u s p r o p e r t i e s of v a n a d i u m in the t e m p e r a t u r e r a n g e 180 to 250 K. A n u m b e r of t h e s e w e r e r e v i e w e d by W e s t l a k e 2 and it was s u g g e s t e d that m a n y of the a n o m a l i e s might be due to the p r e c i p i t a t i o n of i m p u r i t y hydrogen as v a n a d i u m h y d r i d e . Since that t i m e a n o m a l i e s in an Xr a y study of phonons in v a n a d i u m 3 and in the e l a s t i c p r o p e r t i e s of v a n a d i u m 4 have b e e n shown to be a t t r i b u utable to h y d r o g e n i m p u r i t y . F u r t h e r s u p p o r t of W e s t l a k e ' s p o s t u l a t e of the i m p o r t a n c e of h y d r o g e n i m p u r i t y to t h e s e a n o m a l i e s has been obtained by t r a n s m i s s i o n electron microscopy. 5 One of the p r o p e r t i e s r e p o r t e d l y exhibiting a n o m a l o u s b e h a v i o r is the e l e c t r i c a l r e s i s t i v i t y . T h e r e does s e e m to be plenty of evidence to the c o n t r a r y , however. In Fig. 1, p o l y c r y s t a l l i n e v a n a d i u m s p e c i m e n s of d i f f e r e n t p u r i t y exhibit no a n o m a l i e s , but i n d i c a t e , i n s t e a d , that dp/dT is a continuous function of t e m p e r a t u r e , w h e r e p is the r e s i s t i v i t y . 6-8 In the m o s t r e c e n t p u b l i c a t i o n 9 on the subject of e l e c t r i c a l r e s i s t a n c e for v a n a d i u m , an a n o m a l y , Fig. 1, was r e p o r t e d for the [110] d i r e c t i o n in a single c r y s t a l . B e c a u s e the c r y s t a l l o g r a p h i c d i r e c t i o n , which is a p o s sibly r e l e v a n t v a r i a b l e , had not been dealt with in the e a r l i e r i n v e s t i g a t i o n s , and b e c a u s e this new r e s u l t was r e p o r t e d l y s u b s t a n t i a t e d by X - r a y d i f f r a c t o m e t r y , we had to c o n s i d e r the case of v a n a d i u m a l l o t r o p y r e opened. EXPERIMENTAL Two s i n g l e c r y s t a l s of v a n a d i u m w e r e u s e d . F o r m e a s u r e m e n t of the e l e c t r i c a l r e s i s t i v i t y in the [110] d i r e c t i o n , the m a t e r i a l was the s a m e a s d e s c r i b e d in Ref. 10, but the high p u r i t y i n d i c a t e d by the t y p i c a l a n a l y s e s of the s u p p l i e r s e e m s to be b e l i e d by the fact that its r e s i s t i v i t y ratio r = P300 K/P6 K was only about 6. The m a t e r i a l for the other e x p e r i m e n t s was des c r i b e d in Ref. 8 and had r -~ 27. Single c r y s t a l s of the two m a t e r i a l s w e r e obtained by the technique d e s c r i b e d in Ref. 11. The r e s i s t i v i t y a p p a r a t u s was the s a m e a s u s e d e a r l i e r .8 The e l a s t i c c o n s t a n t s w e r e m e a s u r e d by the s a m