222 HOW TO STUDY BIRDS 



been so packed, I should have lost half my stock 

 where they could not be replaced. It was on an ex- 

 pedition among the Florida keys. The heavy boxes 

 of plates were stored in the hold of our vessel, and 

 one night the craft sprang a-leak. In the morning 

 the crates were half submerged. By putting the in- 

 dividual dozen-plate boxes on the deck in the breeze, 

 they finally dried out, and only the rims were spoiled, 

 where the strips stuck to them. Had the faces been 

 in contact, they would all have been welded together. 



The problem of changing plates is rather a trouble- 

 some one afield, where there is no dark-room. Ordi- 

 narily one must wait till night, yet sometimes when 

 all the plates in the holders have been exposed, one 

 may need a few more at once very badly. A 

 11 changing-bag " will serve to transfer a few in an 

 emergency. Where I have been without one and 

 needed plates very much, I have managed to change 

 a few successfully under heavy blankets, or in a small 

 closet on a vessel under a canopy, with all cracks 

 stopped up. Ordinarily, however, one must wait un- 

 til dark, which in northern latitudes is not before 10 

 P. M. Sometimes I have had to do it in the open, 

 as when exploring the great mangrove swamps of 

 southern Florida without a tent, where the mosquitoes 

 were after me in such swarms that I could not help 

 mashing some of them between the plates as I packed 

 them. 



When there is bright moonlight I change plates 

 under a blanket. Perhaps moonlight would not fog 



