F2 MISC. PUBLICATION 225, U. 8. DEPT. OF AGRICULTURE 
TaBLE 19.—Area of large circles } 
Diameter Area Diameter Area Diameter Area 
Feet-inches eae ° | Acres || Feet-inches| “37° | Acres _ || Feet-inches : theta. | Acres 
1 | osetia 78. 5 0.0018 || 87-38. _---~___ 1, 089 0.025 || £60_________ 7, 854 0.180 
TL rome ee 100. 0023) || 502 es. ee 1, 963 - 045 || 105-4___-__- 8, 712 2 
| oes aed SS 113.1 2 O026 41 (52-85 ae 2,178 -05 Le —O eee as 10, 890 20 
1 Liye adele sels a 176. 7 . 0041 |} 55-5_______ 2, 500 OD ||PIZ9E = See 13, 068 
1 eerie neat Me 201.1 . 0046 || 60__________ 2, 827 S065) | PSO = eee 14, 520 3314 
20 sete ee 314. 2 . 0072 |} 61-10____ 3, 000 . 069 |} 188-2_______ 15, 000 34 
Pap al fo i 409, . 0092 |} 64-6_________ 3, 267 ~@75 || 148-11_____ 17, 424 4 
PY es 436 010 (eee EX e 3, 421 = OOF OS — (a= eee 29, 060 46 
rai enn a ree ad 491 O11 (iit ee SAL 2 4, 000 . 092 || 166-6______- 21, 780 5 
aise ean ees Wes 500 O11 74-6_..---- E 4, 356 ae | 203-11_____ 32, 670 75 
Ob eee oe 2 707 016 Vien ess 4,418 STO e235 —6 es see 43, 560 1 
SOeG eee shoe 1, 000 023 CAD es Sa 5, 060 . 115 
1 The value in heavier type is that from which the corresponding values were computed. 
2 Area in square feet=diameter in feet squared multiplied by 0.785398163. 
TABLE 20.—Number cf trees per acre by various methods of spacing 
Spacirg (feet) Trees Spacing (feet; Trees Spacing (feet) Trees 
Number Number Number 
DISG 2 ire jk Ses Re 10, 899 (i Co A es Ws aes IP) Nee eee 242 
Sone Se Le wen 4, 840 (AN) Me ay Ss ee O22, M2 Ss see ees ee 202 
WSCA rest) te SE Ee Ppa? RAD 2 oe Me Se SE Ee LOL peel 220s eee ay eee eee 182 
A SGD mere. sins BO ee 2,178 COA A Ye SEI Se ABW T2252 See ees 2a Oe 145 
AG sg Se ee 1, 815 Cop Coa ce ee GS1F BIB S< 13s See eee ee 258 
ANG [Sse Bi eS © 1555 SK OE ere eed SER oe GOODE MUS ees Bee ee 223 
ANC Sees to ie ere 1, 361 SSGIQE eS ke ENN ISON ee SS 138 
ASCO they 5 ets Wok I 1, 210 8125 Gass af Lah See: AB AS BG 208 ke. ac eres 134 
ASO eee 2S Ts 1, 089 CS) Gilt Ae eR a 2 303 UA LAS eel ener 222 
Deb atee reed 2! Ree 1, 742 SK252 Sa ee a ese ZS IA Ke eS Hee! eee 207 
SDC Osh ee Boo. 1, 452 QC se se ae tagtsy | IGE AN ee 2 EE ee 156 
B@ies eed ees 1245 Ne OSCIO: eae gee 18 ess ARAG IASC On) ne ERO ae ae 124 
Be Bia erne E og 5 Oe 1, 689 OSGUID hs Saas Oe ZA DSi SAL 0 Line eee as MCN 194 
BK Query eee Pt 938 QSC15 «FOR Nig ee YAS lil USO sae eS ee 145 
SPO ae weet coe a NE ST ial LO: eee eras Aa AZ One D< 20s fee ee ee ee 116 
GDhO set sees tee Oe RS SAO ciel O22 see ee Se SOS ON LOR eee eo eee 170 
OD6 ge eee a TS UBIO ij 2 oe se Les 290K HOD 20) ee ee ee 136 
(Co ati Ant aes a Se SOS SlODGIS =o eee Sere ZAZA LOG 2) Se ee ee 109 
GSK O yiany) Bee ees SORE Was ee See SOU || ASU Se see ee ee 134 
GSGIO se ee See a TPAD PA UID PAs t ee ee eee SOOM IMs ZO wee ee ee ee ee 121 
OGIO ee ES ER ee G05) I GIO eS Sere ae ae ee 2048 GALS CZs eee ee ee 97 
GS< loa ae Be AA Th li OO L = ies ey Ae ee oe LOSR E2020 Sees eee 109 
EX Ge pe 2 ees SBOE Ke 2 5: Sen ae TO SM 20625 eee eee ee 87 
ER Bq aes ee See eel GEL ar Sa GD es a Sree a a SOZE|BZ5 C25 eee eee eee 7 
TaBLE 21.—Crades and slopes per 100 feet horizontal 1 
GRADE PERCENT AND EQUIVALENT DEGREE OF SLOPE 
| 
Grade Slope in Grade Slope in Grade Slope in Grade Slope in | 
(Percent) degrees (Percent) degrees (Percent) degrees (Percent) degrees | 
| 
° J ° / 7 ° /, | 
| Mee QO 34.4 1D (See ee 6 16.6 PALS nb ae 1 56 Do maeee see TS 28 438.6 | 
7 sie, es ap teeta 1S id, Pts Coe ee ee 6 50.6 Ppa Sass eh 12 24.4 (ai) eae ee 30 «(57.8 
Geet SES Le 1 43.1 BiB ye ee 7 24.4 Paves alee 2 e542 Gbnegns tee 33d 4 
Aut eke 2 17.4 PA Sete C5852 7), ete TSP PRE 7 (AU a eies Jaleo 34 59.5 
Sete eye 2) Oleh ilbycame eee 8 31.8 Zoek. Biss. A 2852 (OLS 36 52.2 
Gee ep Pk 3 26:0 HGR Aa ee 9 56.4 Bi) ee oe 16 42.0 SOM Se ee 388 39.6 
GES BPS oe 4 0.3 Ae SE os 9 38.9 ee ae a 19 17.4 Bbases ssid 40 21.9 
Slee ee Fk 4 34.4 ite ee oe NOs eZ AQrae 22. 21 48.1 OO wees as 41 59.2 
tO) iss ae ee Om 1856 AO ere OT 10 45.5 A eee ok = 24 13.7 OF bag) aac 43 31.9 
ea I) Yee a 9 5 42.6 7A ey ee 11 18.6 i) eee oe 26 33.9 1LO0zsS2225 45 0 
1 Equivalents of customary expressions of grade are as follows: 
Grades and slopes: 1 foot per chain=1.515 percent; 1 foot per mile=0.018939 percent; 1 millimeter per 
meter=0.1 percent; 1 foot per thousand=0.1 percent; 1-percent grade=633.6 inches per mile=52.8 feet per 
mile=10 millimeters per meter=10 feet per thousand feet=1 foot per 1.515 chains=0.66 feet per chain. 
