OF SEL BORNE. iic, 
during the laying-time. If more than one was come down out of 
the ovary, and advanced to a good fize, doubtlefs then flie would 
that fpring lay more than one. 
I will endeavour to get a hen, and to examine. 
Your fuppolition that there may be fome natural obftruflion in 
finging birds while they arc mute, and that when this is removed 
the fong recommences, is new and bold : I wifli you could dif- 
Cover fome good grounds for this fufpicion. 
I was glad you were pleafed with my fpecimen of the capnmulgv.s^ 
Or fern-owl ; you were, I find, acquainted with the bird before. 
When we meet I fhall be glad to have fome converfation with 
you concerning the propofal you make of my drawing up an account 
of the animals in this neighbourhood. Your partiality towards my 
fmall abilities perfuades you, I fear, that I am able to do more 
than is in my power : for it is no fmall undertaking for a 
man unfupported and alone to begin a natural hiftory from his 
own autopfia! Though there is endlefs room for obfervation in 
the field of nature, which is boundlefs, yet invefligation (where a 
man endeavours to be fure of his fads) can make but flow pro- 
grefs ; and all that one could coUeft in many years would go into 
a very narrow compafs. 
Some extrads from your ingenious " Inveftigations of the dif- 
ference between the prefent temperature of the air in Italy," &c. 
have fallen in my way-, and gave me great fatislacliion : 
they have removed the objedions that always arofe in my 
mind whenever I came to the paffages which you quote. Surely 
the judicious Virgil, when writing a didadic poem for the region 
of Italy, could never think of defcribing freezing rivers, unlefs 
fuch fevcrity of weatlier pretty frequently occurred ! 
P. S. Swallows appear amidft fnows and froft. 
S L E T T E ?>. 
