80 BULLETIN 846, U. S. DEPARTMENT OF AGRICULTURE. 
KnorRR APPARATUS VS. JOHNSON APPARATUS FOR ETHER EXTRACT DETERMINATION. 
As many food laboratories are equipped with the Johnson appa- 
ratus but not with the Knorr apparatus, which has almost invariably 
been recommended for egg work, a comparison of results using the 
two was made, extracting in all cases for 3 hours. 
TABLE 31.—Percentage of ether extract obtained by using Knorr apparatus and Johnson 
apparatus. 
Knorr. Johnson. 
Sample an ; | “ : ‘ 
No: Initial of analyst. Using Using Using Using 
2.54 5.04 25+ 5.04 
grams. | grams, | grams. | grams. 
Per cent. | Per cent. | Per cent. | Per cené. 
[Biscay een Ha ec arta le easel Doar ae oa 10. 64 10.72 10.74 10. 70 
Dawe Gn SU eels Tierra Oley Ua em RE EE Base! TY IS 10.54 10. 46 10.46 10.51 
1G) Ueeeeton cee oS oe iS Lauper Oh aes core a B 10.51 10.52 10.30 1088 
Ee ee ek Ne eee ee ns, tae on ee 10.31 10. 44 10.13 10.17 
Ga vielen: dee ae ee eet eke oa eT 10.60 10.52 10.70 10.46 
[2 aS er 8 5 tigate ae elprer ien a es oak ls er el Sean 11.16 11.15 11.18 11.22 
Spi Dee were! oe ee Se cee es 11.56 11.58 12.78 11. 46 
olga tae ee Meo elew Samy ela Te cL igh baer aN we Ey “nhs 10.88 9.89 10. 64 10.81 
Sai hdd ile Pst te iN a aie ae NN Nae: OO Sls 11.33 11.14 11.33 11.18 
Doe hee ak eh ean a ee Pie aie 12.36 12. 47 12.44 12.45 
[DGS VEE eed RINE Cail ah tle INN (elation tS 13.12 12. 85 12. 65 12.84 
1s hye (La Rechehet eho eeel, Soinnore tye ohn Cnte mn uated isan fn 13.00 12.63 12.60 12.82 
SES, Wipe Aa 8, ie a Lai Ae ee PRI Rey ot 11.63 12.90 11.97 12.11 
Dea” ROD eh PREY ae RRA MIA Saya aiid. Pe 11.76 11.75 11.71 11.54 
eee ee ee ihe et alae Sap Mies A Wah tate nb reyes cd 11.57 11.50 11.50 11.47 
Sask... pecunale ase omeped: Rete fuel 3 11.34 11. 46 11.55 11.42 
GPapee er epee ehh in pe ln ee ete ty tee poy eae 11.57 12.41 11.42 11.32 
TOSS ea aR Me ICN si ere M MN CE Uti chet: Bota Ge 2 Ve 6.07 5.84 5.83 5.67 
TSG EL eee ceo at. Tere ly Pee ree iee Vy E eee 8 5.59 5.59 5.59 5.42 
IRR Re RO Nt SCR AIH ete RAI SE abi a hc 5.94 5.90 5.91 5.88 
IASVIGT AL Ca. ece eo cia aie wie ove Sale aie eee etelere eieie a etorasietelate 10.57 10.53 
It is evident that the Johnson apparatus may be substituted for 
the Knorr apparatus, although the Knorr should always be used if 
possible. 
Errect of TIME OF EXTRACTION UPON THE ETHER ExtTRACT DETERMINATION. 
Nothing is gained by prolonging the extraction for more than 3 
hours, as is shown by the results given in Table 32. 
TABLE 32.—Percentage of ether extract obtained during varying periods of extraction. 
pare Extracted | Extracted 
Vo. 
3 hours. 16 hours. 
Per cent. Per cent. 
10. 24 a 40 
10.13 5774 
3972 10.23 10.32 
10.15 10. 22 
10.19 | 10. 29 
