S Ohservatiom and Experiments^ ^A 



was the wonderful change of temperature, in so short 

 a space of time ! And it seems worthy of observa- 

 tion, that the epidemic Catarrh, which had prevailed 

 universally, during the mild season immediately pre. 

 ceding, suddenly disappeared on the approach ol the 

 late intense frost, but, on the commencement of this 

 sudden thaw, began to re-appear, together with the 

 rheumatic ajQTections of the former period. 



On similar occasions, I have repeatedly remarked, 

 that, on the breaking up of a frost, people are pecu- 

 liarly susceptible of cold : hence, at such times, the 

 incessant coughing in churches and public assem- 

 blies, resembling the attack of a general influenza. 



^ery. Is a sudden transition from a cold to a 

 warm, or from a warm to a cold atmosphere, the most 

 injurious to the human frame ? 



May you, my dear friend, long continue *' toius 

 iercs atque rotundus :''"' in other words, full proof 

 against both, and all the other vicissitudes of our 

 changeful climate. 



A. F. 



Additional Remarks on the Climate of London and Pbi- 

 ladt'lpbia. — Evaporation. — Scale of Heat erdarged. 



Such an intense degree of cold, in England, as to 

 sink the mercury below zero, perhaps, scarcely oc- 



