M. Lassaigne on Stearic JEther and Stearate of Methylene. 487 



between the particles of arsenious acid and water, which did not pre- 

 viously exist." 



Note. It remains to be explained why 1000 grains of a saturated 

 and cold solution, as in Experiment 6, contained 26 grains of arsenious 

 acid, whereas by Experiment 7, it appears that an equal quantity of 

 a solution also saturated and cold contained only 18*7 grains. — R.P. 



STEARIC iETHER AND STEARATE OF METHYLENE. 



M. Lassaigne obtained the above-named compounds by treating 

 stearic acid with a mixture of alcohol and sulphuric acid, or by a mix- 

 ture of the same acid with pyroxilic spirit. 



Stearic aether has the following properties : it is solid, white, and 

 semi-transparent like wax ; it is lighter than water; its odour is not 

 very marked, but is slightly ethereal j it is tasteless, and does not act 

 upon litmus paper. The fusibility of this compound is so great that 

 it melts when pressed between moderately warm fingers, or when rubbed 

 in the palm of the hand j it is insoluble in water, but soluble in alco- 

 hol, and more so when hot than cold. When treated with a hot so- 

 lution of potash, it gradually decomposes, and there are reproduced 

 stearic acid, which remains combined with the potash, and alcohol, 

 which is disengaged with the vapour of water. It appears from ana- 

 lysis that this aether consists of 



Stearic acid 87*9 1 



.-Ether 1209 



100- 

 or an atom of stearic acid combined with one of aether. 



The stearate of methylene, prepared by heating stearic acid with a 

 mixture of sulphuric acid and pyroxilic spirit, is solid, and lighter than 

 water ; it is a confusedly crystalline mass, which is yellowish and se- 

 mi-transparent; its smell is very slight. It softens between the fingers, 

 and soon fuses ; its melting point is about 90° Fahr. It does not act 

 upon litmus, is insoluble in water, and decomposed by hot alkaline 

 solutions. This compound, with respect to the relation existing be- 

 tween its elements, seems to approach the oxalate of methylene and 

 analogous compounds. — Unstitut; Aout, 1837. 



METEOROLOGICAL OBSERVATIONS FOR SEPTEMBER 1837. 



Chiswick. — Sept. 1. Cloudy: thunder showers. 2. Cloudy and fine. 



3. Showery. 4. Cloudy: clear and cold at night. 5. Hazy: cloudy 



and fine. 6. Foggy : very fine. 7. Fine. 8. Rain : sultry. 9, 1 0. Cloudy. 

 11. Fine. 12 — 14. Cloudy and fine. 15. Clear. 16—18 Overcast. 



19, 20. Very fine. 21, 22. Foggy : very fine. 23, 24. Dry and windy. 

 25, 26. Clear and fine. 27, 28. Cloudy and fine. 29, 30. Foggy : 



very fine. 



Boston. — Sept. 1. Fine. 2. Fine : rain p.m. 3. Cloudy : rain a.m. 



and p.m. 4. Cloudy. 5, 6. Fine. 7. Cloudy. " 8. Fine. 



9. Cloudy : heavy rain p.m. 10. Fine. 1 1. Fine : rain p.m. 12. Fine. 

 13. Cloudy: rain early a.m. 14. Cloudy: rain a.m. 15. Fine: ram 



P.M. 16. Cloudy: rain p.m. 17. Cloudy. 18. Cloudy: rain 



early a.m. : rain a.m. 19—21. Cloudy. 22—24. Fine. 25. Fine : 



rain a.m. 26. Fine. 27 — 29. Cloudy. 30. Fine. 



