[5] VERRILL—DREDGING APPARATUS OF U. 8. FISH COMMISSION. 69 
The dimensions of the rake-dredges of this pattern, used by the Fish 
Commission, are as follows: 
Inches. 
Side-pieces of the A-shaped frame, length .......... UD vos Dillons 30 
Side-pieces of the A-shaped frame, width........-...--..22-s.-.s%% 2 
Side-pieces of the A-shaped frame, thickness ..........6.--.5..-0 Z 
Side-pieces of the A-shaped frame, hole for ring........-......... 3 
Side-pieces of the A-shaped frame, hole for bolts............. hee 
@ross-Dar of the A-shaped frame, leneth. .- . a... 5. -cce ee ween ccs 42 
@ross-bar ot mie A-shaped frame, width), ... 2. co... 2s Seceke nals <lts 23 
@ross-bar of the A-shaped frame, thickness.... -..-. +--+... 024-6 2 
rice Hemen ay elomeatiie na howe leas. irae nine en tS dst ieaes 36 
Rake-bars (d), width... -).--- +--+ :ee 22s) ee ee cree ee eee ee eee 24 
Rake-bars (d), thickness .............- a Play PEE HOA ak cn Baar 3 
Mere imOe ed ce LOMO bye > acts ty aisle heh sic isiay> SP) jaiehe, Since Slate pate lovaa lorie et eys nS 
Maram teRelce vevyMGL Ul 52 cteve- are ck Apinles ON he alin'sl Wis Thacais fh wave lela gee eaeee 14 
Piet igtake at WICKMeESS es sc inhe tacks ao She kale aia ale 2 Le Oo abe ieee 3 
PrP REO TEAS oLO NE CLA UAObEL stage sreatierern. (ss oat shal (slolepeyy ele aa ater oS 
PN oMOMUrae TOPE SIZGsOl IPONe a. seer ts Cakes Jelsjab so aee ste,© 3 
Omelette! (7), MOM UM ake iets sci) ees Nee ALy of) RI th ye OBR 38 
Dredge-frame, breadth .-........-.- SE ne re eer Se. Poh fe en t 
eR Cetra e, MOMS Gl OL ARIS ie = ake \< aictols y's oa Sis, Sep e'te sain fel syne 20 
Dredge-frame, size of iron (round) ..........----- Be ROTA Pract tee I Ma) 
2 COpOB Gy S12) we U2) Nes Pes Casares oa oleh eS Ts Bete ten tone ONCE one REOPRR IPE a ie a Bot bP 48 
These dimensions might be improved by making the teeth 10 inches 
long and at least one-half of an inch thick, if of soft iron, and they 
should have a forward curvature. The head, passing through the bar, 
should be square and about three-quarters of an inch thick. They might 
be fewer and farther apart without detriment, say, five teeth on a bar 3 
feet long, leaving the spaces about 6 inches each. The use of steel, of 
low temper, would be better still. The round iron for the dredge- 
frame should be at least five-eighths of an inch in diameter for the size 
of net given. 
During the present season another form of rake-dredge has been de- 
vised by Capt. H. C. Chester, of our party, and used with excellent suc- 
cess. In this the teeth are attached directly to the two sides of a strong 
and heavy rectangular iron frame, much like the frame of an ordinary 
dredge of large size. The teeth are curved well forward and about 10 
inches long. The rake-frame is followed by a lighter net-frame, of the 
same size as in the one previously described. 
THE TANGLES. 
Figure 7. 
The original form of tangles, constructed by the writer for the United 
States Fish Commission, in 1871, consisted of a bar of iron to which sev- 
eral small iron chains were attached, each about 14 feet in length. 
