Intelligence and Miscellaneous Articles. ~65

Apophyllenic acid dissolves slowly and with difficulty in water ; and, except when the solution is made in hot water, the octahedral crystals are obtained slowly. When the acid is made to crystallize by cooling a boiling sulution, the crystals occur in long aggregated prisms, the form of which could not be determined ; they do not ef- floresce, and are insoluble in alcohol and water.

The taste of this acid is slightly sour and astringent. When heated, it melts, carbonizes and disengages an oleaginous substance, which, to judge by its odour, must be quinolein ; and it possesses a strong alkaline reaction.

Apophyllenic acid appears to form soluble salts with all bases ; its ammoniacal salt crystallizes in tables ; it is very soluble, and gives no precipitate with the salts of barytes or of lead. I t does not im- mediately form a precipitate with a salt uf silver, but after a few minutes have elapsed, small stellated crystals are produced, which soon form small grgups of fine white needles. This salt of silver de- tonates with as much facility as the oxalate, when heated. The small residue of the detonation is composed of a coaly mass, which leaves spongy metallic silver. This acid was obtained during the preparation of eotamina.--Ann, de Ch. et de Phys., October 1844.

A N A L Y S I S O F H Y P E R S T H E N E .

M. Damour has recently analysed a specimen of this mineral which belongs to the Ecole des Mines, and which is ticketed as coming from Labrador.

It is a lamellar mass, cleavable only in one direction ; colour black, with a brilliant bronze reflection. Powder gray. Fractures readily into small laminae and very minute needles. Specific gravity 3"392. Scratches glass feebly. Attracted slightly by the magnet. A thin portion heated by the blowpipe fused into a black enamel ; gave no water when heated in a tube ; fused with carbonate of potash and a little nitre; on platina foil gave a green-coloured substance, indica- ting manganese. Hydrochloric acid attacks i t with diffioulty.

I t yielded by analysis ,-- Silica . . . . . . . . . . . . . . . . 51"36 Protoxide of iron . . . . . . 21"27 Manganese . . . . . . . . . . 21"31 Lime . . . . . . . . . . . . . . . . 3"09 Protoxide of manganese. 1"32 Alamina . . . . . . . . . . . . . . 0"37

98"72 Annales des Mines, tome v. p. 157.

P R O T O X I D E O F T I N A N D T H E A L K A L I E S . B Y M . F R E M Y .

I t is well known that protoxide of fin dissolves in the alkalies, the sulution has, however, been hitherto but little examined. I t is ge- nerally admitted, according to the experiments of Proust, that a so- lution of protoxide of tin in potash deposits metallic tin, and retains

366 Intelligence and Miscellaneous Articles.

stannate of potash in solution. According to BerthoUet, jun., the solution yields anhydrous protoxide of tin by evaporation.

M. Fremy states that anhydrous oxide of tin is not soluble in a weak solution of potash ; and whenever the hydrate in solution can be deprived of its water, it quits the alkali and is precipitated; this curious property induced the author to examine the circumstances under which protoxide of tin can be dehydrated.

In the first place, it was found that the hydrate may lose its water in a solution of potash ; if the hydrate be boiled in a very dilute so- lution of the alkali, it is in a very few minutes converted into small brilliant black crystals of anhydrous oxide of t in ; the influence of the alkali in dehydrating the oxide is evident, for when equal quan- tities of hydrated protoxide of tin are boiled, one in pure and the other in alkaline water, the latter is very rapidly dehydrated ; on the contrary, i t requires a very long time to dehydrate the oxide in pure water.

Heat is not indispensable to cause an alkali to dehydrate oxide of tin ; for if a solution of potash and hydrate of tin be put under the receiver of the air-pump, the oxide becomes anhydrous as soon as the potash is sufficiently concentrated.

These experiments explain the decomposition which a solution of oxide of tin in potash undergoes; this solution cannot be made without an excess of alkali, and as long as the solution is weak the oxide remains dissolved; but when the liquor is concentrated, the oxide is dehydrated, and precipitates in that state. On this account it is impossible to evaporate, even in vacuo, a solution of protoxide of tin in potash, without observing that at a certain point of the concentration the liquor deposits anhydrous oxide of tin. These facts agree with those observed by Berthollet, jun. ; they show that protoxide of tin dissolved in a dilute solution of potash may be de- hydrated and precipitated anhydrous.

In order to repeat Proust's experiment, protoxide of tin was dis- solved in potash, and instead of evaporating the solution slowly, as in the preceding case, it was submitted to rapid evaporation; the protoxide of tin was then decomposed, the liquor deposited metallic tin and held stannate of potash in solution ; it is therefore evident that the products of the decomposition vary with the concentration of the alkali ; when the liquor is dilute and weakly alkaline, anhy- drous protoxide of tin is precipitated, and it is only when the alkali is concentrated, that the protoxide is converted into tin and stannic acid.

These experiments show that dehydration takes place more readily in a hot solution of potash than a cold one. Must it then be ad- mitted that a solution of potash, even when dilute, has an affinity for water and can take it from an hydrated oxide ? or may not these effects be explained by the interesting experiments of M. Mitscher- lieh on *etherification, which prove that a certain quantity of sul- phurie acid may convert alcohol into ,ether almost indefinitely ? The author thinks it is difficult at present to explain the fact in a satis- factory manner; but he found that solution of sulphate of soda,

Meteorological Observations. 3 6 7

c h l o r i d e of p o t a s s i u m , c h l o r i d e of s o d i u m a n d h y d r o c h l o r a t e of a m - m o n i a , w e r e c a p a b l e w h e n h e a t e d o f d e h y d r a t i n g t h e o x i d e of t i n r a p i d l y . T h i s a c t i o n o f t h e c h l o r i d e s i s t h e m o r e r e m a r k a b l e , b e - c a u s e t h e y c r y s t a l l i z e i n t h e a n h y d r o u s s t a t e .

P r o t o x i d e o f t i n , w h e n d e h y d r a t e d u n d e r t h e c i r c u m s t a n c e s d e - s c r i b e d , d o e s n o t a l w a y s a p p e a r i n t h e s a m e s t a t e ; i t i s s o m e t i m e s b l a c k a n d c r y s t a l l i n e , a t o t h e r t i m e s b r o w n , a n d o f t e n as r e d a s minium.--Ann, de Ch. et de Phys., D e c e m b e r 1 8 4 4 .

M E T E O R O L O G I C A L O B S E R V A T I O N S F O R F E B . 1 8 4 5 .

Chiswick.--February 1. Sharp frost : snow-showers at night . 2. Clear and frosty : cloudy : clear and frosty. 3. Hazy and drizzly. 4. Overcast : cloudy : frosty. 5. Overcast: f ine: clear. 6. Clear throughout : sharp frost at night. 7. Frosty : overcast : clear and frosty. 8. Overcast : frosty. 9. Clear and frosty : fine : sl ight frost. 10. Overcast : snowing. 11. Frosty : most intense frost a t night, the lowest being 35 ° below the freezing-point. 12. In tense frost, only 4 ° above zero at 8 A.ra. : dry air and frosty : br ight sun : severe frost at night. 13. Overcast : snowing: sleet and rain. 14. "l 'hawing: clear and f ine: overcast. 15. Clear and frosty. 16. F i n e : densely overcast: frosty. 17. Foggy : fine : clear and frosty. 18. Foggy : hazy clouds. 19. Overcast : clear : frosty. '20, 21. Clear and frosty throughout . 22. Snow-showers : foggy. 23. Snow : rain. 24. Cloudy and cold. 25. Frosty : fine : rain. 26. Clear : fine : densely over- cast. 27, 28. Overcast .-- Mean temperature of the month 8 ° below the average.

Boston.--Feb. 1. Cloudy: snow A.M. and e.~. 2. Fine. 3. Cloudy : rain • ~.M. and P.M. 4. Cloudy. 5. F ine : stormy night. 6. Windy. 7. Fine. 8. Cloudy. 9. Fine. 10. Snow. 11, 12. Fine. 13. C loudy : rain and snow A.~t. 14, 15. Fine. 16. Cloudy : rain early A.~t. 17, 18. Fine. 19. Cloudy. 20. Fine. 21. Foggy. 22. Cloudy. 25. Snow: rain r.•. 24. Cloudy. 25. F i n e : r a i n P.M. 26. Fine. 27. Cloudy. 28. Fine.

The above you will find a very cold month ; I think .~ ou will find nothing l ike i t since February 1838.

Sandwick Manse, Orkney.--Feb. 1. Frost : cloudy. 2. Rain . 5. Br ight : cloudy. 4. C lou dy : sleet-showers. 5. Snow-showers. 6. Snow-showers: snow-drift. 7. Snow-showers. 8. Snow-showers : clear. 9, IO. Thaw : cloudy : drops. 11. Clear : showers. 12. Cloudy : showers. 18. Showers. 14. Snow: cloudy. 15. Showers: cloudy. 16. F o g : cloudy. 17. Br igh t : clear: fine. 18, 19. F ine : cloudy. 20. Showers. 21. Showers: c lear : fine. 22. Showers: snow-showers. 23. Showers. 24. Cloudy : clear : aurma. 25. Clear : cloudy. 26. Cloudy : c lear : frost. 27. Br ight : cloudy. 28. Cloudy : clear.

Applegartlz Manse, Dumfries-sldre.--Feb. 1. Frost. 2. Severe frost : rain P.M. 5. Fine thaw. 4. Frost : thaw e.M. 5. Thaw A.r~. : frost e.~z. 6. Frost : clear and fine. 7, 8. Hard frost. 9. Snow. 10. Slight thaw. 11. Snow-showers. 12. Frost A,~. : rain P.M. 13. Heavy rain. 14. Fro~t : shower : snow and hail. 15. Frost : thawP.M. 16~ 17. Fine. 18. Fine spring day. 19. Fros t : fine. 20. Slight frost : fine. 21. F ine : no frost. 22. Slight frost : snow. 25. Slight frost : fine. 24. Frost : ra in P.~. 2.5. Fresh : fine. 26. Frost A.M. : fine. 27. Frost. '28. Frost : fine.

Mean temperature of the month . . . . . . . . . . . . . . . . . . . . . 540"5 Mean temperature of Feb. 1844 . . . . . . . . . . . . . . . . . . 82 "9 Mean temperature of Feb. for twenty years . . . . . . 56 "0