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are as easily charged. discharged and cleansed as a. Iijeltlahl distilling flask; these operations are per- formed. of course, through the tubulus. Th...
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Sept

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T H E J O 1 7 R S A L O F I S D C 7 S T R I S L -4 S D E S GI -1-E E RI S G C H E M I S T R E'

j e c t i n g i n t o it, 2 o r 3 e m . . a t u b e a b o u t 2 . 9 c m . i n d i a m e t e r (inside) a n d 2 j c m . l o n g ; p r o j e c t i n g i n t o t h e e n d of t h i s t u b e is t h e c o n n e c t i n g b u l b . and i n t o t h e conn e c t i n g lmlb t h e b l o c k - t i n c o n d e n s i n g t u b e . -111 p a r t s a r e soldered t o g e t h e r with ordinary t i n solder, still and c o n d e n s i n g t u b e f o r m i n g o n e c o n t i n u o u s piece. T h e c o n n e c t i n g b u l b , h o w e v e r ! m a y b e disp e n s e d w i t h , as it is of n o t m u c h use. T h e s e stills a r e as easily c h a r g e d . d i s c h a r g e d a n d cleansed as a I i j e l t l a h l distilling flask; t h e s e o p e r a t i o n s a r e p e r f o r m e d . of c o u r s e , t h r o u g h t h e t u b u l u s . T h e t u b u l u s m a y lie s t o p p e r e d ivith a c o r k ; b u t a r u b b e r s t o p p e r is pi-eferred---either i n s e r t e d o r c l a m p e d o n . T h e c l a m p e d - o n s t o p p e r shom-n on still 6 w a s u s e d t w o >-ears. a n d c o u l d d o u b t l e s s b e u s e d s e v e r a l y e a r s l o n g e r . O n e of t h e a d v a n t a g e s of t h e s e stills is t h a t t h e y practically eliminate t h e trouble that stoppers cause i n t h e c a s e of K j e l d a h l distilling f l a s k s ; t h e i r chief d r a w l i a c k is t h e t i m e ( a b o u t I j m i n u t e s t o a s e t of t e n ) c o n s u m e d in t r a n s f e r r i n g t h e d i g e s t a g e . O n l y t h e lower p a r t of t h e s e stills is c o r r o d e d ; n e w b o t t o m s a n d e n d s a r e t h e n s o l d e r e d on. T h e w r i t e r d e s i g n e d a n d u s e d n still of t h i s k i n d six or e i g h t y e a r s a g o . Fil-e or s o y e a r s a g o h e p u t i n t o u s e a s e t of t w e l v e . T h e y w e r e used w i t h e n t i r e s a t i s f a c t i o n f o r t w o y e a r s . u n d e r g o i n g r e p a i r s s e v e r a l t i m e s i n t h e meann*hile. T h e use of t h e m was d i s c o n t i n u e d . b e c a u s e t h e y were t h o u g h t t o lie n o l o n g e r e c o n o m i c a l i n view of tlie c h e a p n e s s a n d d u r a b i l i t y of J e n a glass, a n d i n T-iew of t h e t i m e w a s t e d i n t r a n s f e r r i n g .

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F i g . I11 s h o w s a n o t h e r m e t h o d of c o n n e c t i n g t h e s e c o p p e r stills w i t h t h e c o n d e n s i n g t u b e . n a m e l y , b y m e a n s of a n o r d i n a r y p i p e c o u p l i n g w i t h r u b b e r w a s h e r between. Despite t h e fact that this m e t h o d renders t h e t u b u l u s u n n e c e s s a r y , it was a b a n d o n e d in f a y o r of t h e t u b u l u s . A l t2 2 is shoivn a disc ( c o p p e r o r blockThese t i n ) that is u s e d i n s o m e of o u r c o n n e c t i n g b u l b s . discs a r e s l i g h t l y less in d i a m e t e r t h a n t h e g r e a t e s t inside d i a m e t e r of t h e b u l b s ; a r e l a i d in loose, n o t s o l d e r e d ; t h e y should ha\-e n u m e r o u s notches, a b o u t 0 . j m m . deep, a r o u n d tlie e d g e . T h e s t e a m i m p i n g e s a g a i n s t t h i s disc. p a s s e s a r o u n d it a n d o u t i n t o t h e c o n d e n s i n g t u h e .

1 I a n y t h o u s a n d s of n i t r o g e n d e t e r m i n a t i o n s lia\-e b e e n m a d e m-ith t h i s a p p a r a t u s b y t h e n-riter a n d b y o t h e r s (in t h e case of t h e c o p p e r stills, b y t h e XI-riter o n l y ) . B u t y o u c a n n o t see w h a t is going on in t h e c o p p e r stills? X70u d o n o t n e e d t o . B u t if t h e r e is f r o t h i n g ? T h e r e \\-ill b e no f r o t h i n g . e x c e p t as t h e res u l t of b a d m a n a g e m e n t ; a n d b a d m a n a g e m e n t o u g h t not t o occur oftener t h a n once or twice per thousand d e t e r m i n a t i o n s . Moreox-er, w h e n f r o t h i n g d o e s occ u r . it will m a n i f e s t itself a t t h e receil-er e n d of t h e c o n d e n s e r , a n d t h e d e t e r m i n a t i o n is lost. BUT t h e stills s o m e t i m e s g e t d r y a n d m e l t a p a r t ? T e s . thrr11ig11 gross carelessness. o n c e i n p e r h a p s , a thousancl c a i i 4 . f o r t h e r e is. t o s t a r t n-ith! a b o u t z j o t o ~ ~ O cc'.O of lic!iiiil i n t h e still: t h e distillation is s t o p p e d w h e n aboi:?. io0 c c . of d i s t i l l a t e h a s a c c u m u l a t e d i n t h e receix-er. ~ , A B O R h T O R Y OF

THE S o K T H C A R O L I S A D E P . 4 R T M E S T R1LEIGII.

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ADDRESSES CHEMICAL PATENTS-I

rcference to allied arts such as fertilizers, petroleum produrts, rubber manufacture, etc., all of which in\-olve chemical processes to a greater or less degree.

Bl- S E A B ~ I R C.Y MAS TICK^ Received M a y 11,1915

The subject of chemical patents and of patents for processes relating to industrial chemistry is one of the oldest, if not the oldest, in the realm of patents. As early as 1467 a patent was granted in Berne for the manufacture and sale of paper and in 1507 the Council of Ten in Venice granted an exclusive privilege for twenty years for the introduction of a secret process of mirror-making. During the first ten years at the beginning of the patent policy in England ( 1 j61-70) twelve of the eighteen patents granted were for 7-arious chemical products and processes. The chemical patents related t o such subjects as soap, saltpeter, alum, sulfur, oil, salt, glass, and cloth- and leather-dressing. In the course of the next decade three of the ten patents granted related to chemistry, t'iz. : those for earthenware, glass and sulfur. The marked increase in the study and development of the arts relating to chemistry in the United States during the past decade and more has made i t imperative for all having t o do with the subject to gix-e careful attention to patents, t o the ascertaining of what is patentable, how to properly protect inventive ideas and how to enforce the protection so given, as well as how t o avoid trespassing upon the rights of those holding patents with which the thing you are considering developing may conflict. The importance aut1 development of chemistry in the arts in the T'riited States is shown by the following comparative figures relating exclusively t o the manufacture of, chemicals without ' Special lecturer on Chemical P a t e n t s , D e p a r t m e n t of Engineering, Columbia T-7niversity, 19 15

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