432 



Heating Plant-houses hy Arriotfs Stove. 



amount of about half a cwt. every twenty-four hours for each stove, 

 the heat has been kept up pretty successfully ; and during the 

 time they have been in use here, although the situation is low 

 and damp, scarcely any plants have damped off in the houses 

 where they are; but from the great escape of smoke and dust in 

 lighting, and at each making up of the fires, which averaged, 

 during severe weather, not less than six or seven times every 

 twenty-four hours, the plants became clothed with a most un- 

 sightly black coat of dust, which was not easily removed, and was 

 in many instances, as in the pelargoniums, &c., retained till out- 

 grown. The hours for making up the fires, to keep up as regular 

 a heat as could be procured, were found to be about the following : 

 8 o'clock A. M., between 11 and 12 at noon, 3 p. m,, between 5 

 and 6 p. m., 9 p. m., and between 1 1 and 12 o'clock at night. 



January having been the coldest month during the past winter, 

 I have chosen the register of the thermometer for the coldest part 

 of that month, to show more clearly the amount of heat that these 

 stoves, with the above attendance, are capable of supplying. 



Time. 



Open air. 



Greenhouse. 



Conservatory. 



Jan. 3. 8 morn. 



36° 



43° 



44° 



10 night 



28-5 



44 



43 



4. 8 morn. 



30 



43 



43 



9i night 



31 



48 



44 



5. 8 morn. 



27 



41 



42 



11 night 



28 



48 



42 



G. 8 morn. 



27 



42 



42 



9 night 



17 



45 



— 



111 night 



19 



44-5 



42 



7. 8 morn. 



15-5 



42-5 



42 



5 P.M. 



19 



46 



42 



9 night 



16 



46 



42 



12 night 



16-5 



45 



42 



8. 8 morn. 



8 



37 



38 



8§ night 



10 



43 



40 



12 night 



8 



40 



38 



9. 7 morn. 



14 



42 



38 



9 night 



30 



45 



42 



10. 8^ morn. 



32 



43 



42 



9" night 



30 



42 



40 



11, 8 morn. 



32 



42 



40 



9^ night 



30 



49 



46 



12. 8 morn. 



30 



43 



44 



9 night 



29 



51 



48 



13. 8 morn. 



23 



41 



43 



91 night 



34 



49 



46 



14. 8 morn. 



33 



42 



42 



9 night 



32 



45 



44 



15. 9 morn. 



34 



41 



42 



9 night 



33 



46 



44 



Botanic Garden, Oxford, 



Aug. 1841. 



