eighing of the latter. For ordinary quantitative fat 

 ons A and B may be made from stout test tubes 



than tli 



& W. Johnson— Composition 0/ the Street Potato. 197 



3r ordinary quantitative fat-estima- 

 e from stout test tubes, 

 ly easier to construct and to handle 

 separate interior or exterior tube to 

 rry up the ether-vapors, but has the additional advantage 

 that the substance to be extracted is kept warm by being con- 

 stantly surrounded with hot vapor. 



It is best to mount tin.- apparatus so that it may be put into a 

 somewhat inclined position if needful, as then by revolving the 

 apparatus on the condenser tube D the stream of condensed 

 solvent may be directed in succession on all parts of the con- 

 tents of B and any channels that may form are easily broken up. 

 In milk-analyses I have followed the fat- extraction by similar 

 treatment with 80 per cent alcohol for the separation of sugar. 



II. On the Composition of the Sweet Potato. 



The Sweet Potato {Convolvulus batatas or Batatas edulis) is an 

 esculent of great valui to tin United States. It is not only at 

 bome in all the Southern States, but is produced in large quan- 

 tities in Central New Jersey, and Central Illinois, latitude 40 ; : 

 and has been successfully raised in gardens in nearlv the cold- 

 est parts of New York, as well as in Maine and" Southern 

 Minnesota (St. Paul), in latitude 44 J to 45°. It is probable 

 that under northern cultivation varieties may originate more 

 adapted to cold climates, so that were it needful its ; 

 cultivation might be extended several degrees of latitude 

 northward, as is said to h e happened i F in.] with regard 

 to maize, for which it is asserted that 46° north latitude was 

 formerly tin limit, whereas n it is \ rly to 52°. 



The Sweet Potato is known in many varieties which ditter 



widely 11, quahtv N.ttiunll\ t',e ml- '■ 1. 1 ••• , 



at the north are less sweet and less highly flavored than those 

 produced in a wanner climate. The New Jersey and Delaware 

 sweet potatoes which are marketed in New England, though 

 palatable and largely consumed, are decidedly inferior to the 

 produce of Virginia. I am informed that sweet potatoes 

 of excellent '■ 37°-38°, 



while those produced in Central Illinois, lat. 40°, are "watery" 

 ratively insipid. 

 The sweet pot i'to 1 1 u,_i. s t t p, it it ti e 1 ■rth is t . Nai - - 

 ""'I'd. taking its name from the southeastern county of \ ir- 

 Pima, whereat is said to have originated. The •• \ 

 Improved," raised in Hanover Co.TVa.. is the finest variety ot 

 this esculent that has come under mv notice. 1 am indebted 

 to John Ott, Esq., of Richmond, Va., for abund mt dimples of 

 this variety, the high quality of which has induced me to 

 undertake its analvsis. 



