892 FOODS AND FOOD ADULTERANTS. 
decanted each time and the fractions united. The decanted solution is now boiled 
and passed through a tared filter. The insoluble residue is finally transferred to 
this filter, thoroughly washed with boiling water, dried, and weighed. The total 
weight, less the tare of the filter, is the insoluble residue from which the per cent 
insoluble leaf is calculated. The total extract is determined by difference, deducting 
the per cent of insoluble leaf from 100. 
A weighing tube should be used in weighing filters and residues on filters. 
Half-hour extracts.—This extract is of doubtful value for comparative purposes 
unless certain conditions are adopted and strictly adhered to. Slight variations may 
cause very perceptible errors in the results. I have followed essentially the condi- 
tions indicated by Geisler, which are evidently based on Wanklyn’s method. 
Place 1 gram of leaf tea in a 300 ce flask, add 100 ce cold distilled water and a small 
fragment of paraffin, to prevent foaming. Immerse the flask a minute or two in 
water heated to 90°C. in order to raise the temperature of its contents quickly to 
within a few degrees of the boiling point. Having dried the outside of the flask, 
boil the mixture thirty minutes. The flask must be fitted with a reflux condenser. 
After boiling, cool quickly in a stream of water and filter off the extract. Transfer 
an aliquot part of the extract to a tarred dish and dry. Calculate the per cent of 
matter from the weight of the residue. 
GENERAL REMARKS TO ANALYSTS. 
The analyst must be guided almost entirely by comparisons of his 
work on the suspected teas with the records of analyses of pure sam- 
ples. The microscopic are almost the sole methods of detecting many 
of the adulterants of teas. Questions in regard to quality, where this 
depends upon aroma only, must be answered by a professional tea- 
taster. 
REPORT OF THE EXAMINATION OF SAMPLES OF TEAS BOUGHT IN 
THE OPEN MARKET. 
The samples examined in the course of the investigations were pur- 
chased in stores of all grades. The analyses of these teas and general 
statements concerning them are given in the following tables: 
Description of samples. 
Date | Serial : ee 3 
ot pur- Taber Retail dealer. Sold as-- Cee 
chase. pound. 
1887. | ee 
Feb. 15 4850 | Metzger, Seventh between D and EK | Cheap green tea ..--.----.-.---.-.-- $0. 50 
streets. 
ASST 2 eters GOL seh ae Gcras - eset ad eek epee Cheap blackiteasssaee. eto e eee eee . 50 
4852 | G. G. Cornwall & Soms.--.--:..---.--- Gunpowders sees ee eee 1. 30 
[or ESR ee GOs22 esas See. se eee | \Oolongttéaz (59-452 2292-G._pee aes . 88 
Jan. 18 A860) | FBOW oie dS: SONS) ene a ae eee Reo t ee (8 \ (epee eae rs Mr ed Gaeta eS oe Lo Pi . 60 
4863 | Pacific Tea Store, Seventh street Nw.| Blacktea a2: bene eee ite . 50 
4864 |...... dO Ase ee eee eae SA eee eee “Green tea Wed. aee el eee . 50 
4865 | Brought from China by T. C. Trescot, From a Formosa garden (biack) .---.| -.---- 
‘ esq. | 
Apr. 8 4940 | Metzgers, Seventh street -...--.----.- | Nonip ersiallteapeee nee see eeee eee 1.00 
4941 soe. oe CO KO ence ae yA ae HEL nc tone miaeg isHormosa Oolong Pes ee ee eee eae 75 
4942 | Atlantic and Pacific TeaCo.,Seventh | English breakfast ..........-..----- . 80 
street. 
