• • • 



CONTENTS, "I 



11,12. Daily magnetic variation — Economical process for im- 

 itating silver paper, .... 



13, 14, 15. Pressure of sand — Cement from iron filings — Con- 

 centration of sound, . . - . 



16, 17. Dangerous plant among water-cresses — Thunder storms 



in France, ------ 



Page. 



189 



190 



191 



STATISTICS. 



1. Mortality of infants, - - - - - 



2, 3. Phthisis pulmonalis in Paris — Establishment of a model 



farm in Greece, 



4. Science in Madrid, 



5, 6. Hygiene — English Universities 



192 



- 193 



- 194 

 , ... 195 



ADDITIONAL EDITORIAL SELECTIONS 



1. Dr. Mitchell's method of working caoutchouc, - - 195 



2. Strength of wine and other bottles, - - - 196 



3. Magnesium — Metal of magnesia, - - - 197 



4. 5. Decrepitating common salt — Manufacture of bicarbonate 



of soda, - - - " - 



198 



6, 7. Russia diamond mines — Premature Explosions, - 199 



ADDITIONAL EXTRACTS, BY PROF. GRISCOM. 



1. Force of vapor at different temperatures, - - 201 



2, 3, 4. Safety of steam boilers — Translation of the Mecanique 



Celeste — Germination upon mercury, - - 202 



5, 6, 7. Boring for water — Preservation of iron from rust 



Beet sugar, - - - - - - 203 



8, 9. Hydrophobia — Silicine — P. S. Bedford mineral springs, 204 



