New foods at a banquet

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CURRENT TOPICS.

[J. F. I.

emit a loud, audible note, w h o s e pitch could be studied a g a i n s t the b a c k g r o u n d of a n o t h e r note m a i n t a i n e d at a s t a n d a r d pitch. T h e pitch of the telephone note w a s tuned to this pitch. L e t the distance b e t w e e n the plates in the first circuit change. A change in t h e pitch of the note c o m i n g f r o m the telephone follows, and in consequence there is a difference in the n u m b e r of beats h e a r d in a second. A careful s t u d y s h o w e d that in practice altering the interval b e t w e e n the plates by one t w o - h u n d r e d - m i l l i o n t h p a r t of an inch caused a perceptible change in the n u m b e r of beats per second. T h e t w o notes w e r e b r o u g h t back into unison by m o v i n g the pointer in a variable c o n d e n s e r in the second circuit. W h e n the distance b e t w e e n the plates in the first circuit was m a d e to change b y a relatively large distance, such as one o n e - h u n d r e d t h o u s a n d t h of an inch, it was found t h a t shifting the condenser pointer o n e - t e n t h of a degree c o m p e n s a t e d for s e p a r a t i n g the plates a b o u t three ten-millionths of an inch. T h e m e t h o d is so sensitive t h a t the placing of a British p e n n y on a s t o u t bench s u p p o r t i n g the a p p a r a t u s caused a percdptible audible change, because it b e n t the bench, tilted the s u p p o r t s and changed the distance f r o m one condenser plate to the other. In view of the fact t h a t the w a v e - l e n g t h of the s h o r t e s t w a v e s of visible light is a b o u t one s i x t y - t h o u s a n d t h of an inch it is seen that this new m e t h o d of linear m e a s u r e m e n t can d e t e r m i n e distances v e r y m u c h smaller than the w a v e - l e n g t h of light; indeed, it is applicable to lengths as small as the d i a m e t e r of an atom. G. F. S. N e w F o o d s at a B a n q u e t . - - T h e farewell b a n q u e t on F e b r u a r y I6th tendered to S e c r e t a r y Meredith b y the scientific w o r k e r s of the D e p a r t m e n t of Agriculture, w a s m a r k e d by inclusion in the m e n u of several articles of food t h a t have been m a d e available by the labors of the d e p a r t m e n t . T w o of these articles were m a t e rials, for the p r e p a r a t i o n of which p a t e n t s have been issued to their devisors, but laid open to public use. T h e s e are the " perfect bread," the result of studies by Dr. Carl O. J o h n s and A. J. Fink, b e i n g the first food p r o d u c t f u r n i s h i n g a c o m p l e t e l y balanced ration, and candies m a d e fl-om s w e e t - p o t a t o sirup. T h e f o r m u l a for the latter item has been p a t e n t e d b y D o c t o r Gore. O t h e r items of the m e n u w e r e A m e r i c a n r o q u e f o r t cheese, saratoga chips m a d e f r o m the n e w l y introduced vegetable, dasheen, a new s o y - b e a n sauce developed b y D o c t o r Church and n e w varieties of grapes, i m p o r t e d u n d e r the direction of D o c t o r H u s m a n n . H.L. Cellulose A c e t a t e a n d Artificial Silk. (The Chemical Age.)-Cellulose acetate, f r o m which dope for aeroplanes and airships is made, has p r o v e d itself to be of the u t m o s t value in the aircraft industry, and the conception of laying d o w n and c o m p l e t i n g the