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 — tI 
 
 1 
 
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 1 
 
T 
 
I 
 
 REPORTS 
 
 OK — 
 
 HON. Wm. J. McALPINE, 
 
 AND 
 
 D. M. GREENE, Esq., C. E., 
 
 — ox 
 
 WOOD AND SAWDUST DEPOSITS 
 
 IN TMK 
 
 HUDSON AND OTTAWA IIIVKKS. 
 
 "^UtAUu f: 
 
 27 ^' <^ ■ 
 
 Hue ^nc.i''3. /'* 
 
 OTTAWA : 
 
 I'KIXTKI) HV A. s. WOOnUrUX, Kl.lilN S'I'KKKT, 
 
 187;^. 
 
REPORTS 
 
 — OF- 
 
 HON. W^m. J. MeALPINE, C. E., 
 
 AND 
 
 D. M. GREENE, Esq., C. E., 
 
 — ON — 
 
 WOOD AND SAWDUST DEPOSITS 
 
 IN THE 
 
 HUDSON AND OTTAWA RIVERS. 
 
 VlTIUiAlKKS" )j 
 
 ' t-.. 
 
 j,^^^^ 
 
 pr:>- 
 
 OTTAWA : 
 
 PRINTED HY A, S. WOODBURN, ELGIN STREET, 
 1873. 
 

 
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 |..,,r/. 
 
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 REPORTS 
 
 or 
 
 HON. W. J. M'ALPINE, C.E., AND D. M. GREENE, ESQ., C.E,, 
 
 On Wood and Sawdust Deposits 
 IN THE HUDSON AND OTTAWA RIVERS. 
 
 'I 'hi 
 
 Albany, March Ist, 1871. 
 
 To H. F. Bronson, Esq., 
 Ottawa. 
 
 : ' Dear Sir,— Professor D. M. Greene and myself have disoussed 
 the question which you have presented to us, viz : The effect upon 
 the navigation of the Ottawa Ei\er, of discharging therein the 
 sawdust from the lumber manufactories at and above Ottawa. 
 
 With this you will receive an elaborate and exhaustive report 
 from Professor Greene, which I have carefully examineH and dis- 
 cussed with him, and as I entirely concur therein, I will only state 
 the leading points, and will add thereto, the results of my own 
 observation and experience in regard to this subject. 
 
 As there is no engineering authority which furnishes the 
 specific gravity of saturated sawdust, or of the velocity of the cur- 
 rent required to remove it, Prof. Greene has been compelled to 
 resort to direct experiment, to determine these two points, both of 
 which are necessary to the solution of the question involved ; the 
 results of his experiments ai-e : That the specific gravity of water 
 saturated sawdust, (or of its weight, compared with water) is 1.05 + 
 The velocity necessary to move coarse saturated white pine saw- 
 dust, laying on a smooth bottom of a stream, is 0.282 feet per 
 second, equal to ibout one-fifth of a mile an hour, and of fine saw- 
 dust is 0.246 feet per second, or about ono-sixth of a mile an horn-. 
 
"(:;■ 
 
 i^s 
 
 .1 ; 
 
 ■. '■). 
 
 t-<i 
 
 
 & 
 
 m 
 
 The U. S. Government Engineers ascertained that the sand and 
 even small gravel stones in the Hudson Kiver near Albany, were 
 moved along the bottom by velocities of 1.4 to 1.7 feet per second, 
 and in a few cases with those of even one foot velocity. 
 
 Other standard authorities agree substantially with these 
 restilts. 
 
 The specific gravity of the individual particles of the Hudson 
 Blver sand, is from 2.25 to 2.G6 as they may happen to bo of slato, ' 
 mica, fieldcpar or quartz. 
 
 As sand, or fine gravel with a specific gravity of say 2.5, is 
 moved by a current of say 1.5 feet per second, these experiments 
 and authorities show that Professor Greene's results may be relied 
 upon as substantially correct, as applicable to the case in hand, and 
 therefoi-e that no permanent deposit of sawdust, will take place 
 where the velocity of the current exceeds 0.25 feet per second. 
 
 The mean annual volume of the sawdust cast into the Hud- 
 son; is but one, one hundred thousand part of the volume of the 
 water passing at Albany, or about half a grain to the gallon, while 
 it is well known that a portion of such sawdust is deposited above 
 low water mnvk and is decomposed. All of the remainder, (except 
 that which is not deposited in the shallow side basins,) is undoubt- 
 edly carried forward to the sea. <v: < ? f '.yua j.m./ ti^ni^a tioiimtip 'ac 
 
 Analysis of the water from the very deep places, toward the 
 mouth of the Hudson, show the presence of even larger quantities 
 of material of this character, — and therefore that this sawdust, is 
 certainly carried thus far seaward, and a similar analysis would 
 doubtless show its presence at the mouth of the river. 
 
 That the velocity of the water in the Ottawa River generally 
 exceeds that required to move sawdust forward, is evident from the 
 well known fact that the bars in the wide expansions of the river, 
 are cx)mposed of clay, sand and gravel, all of which required a much 
 greater velocity to transport them to these places, and whenever this 
 velocity was lessened enough to permit of the deposition of these 
 materials it still greatly exceeded that necessary to carry the saw- 
 dust onward. 
 
 ■I ''.: 
 
 :i'(iW\ 
 
 If a deposition of sawdust should happen to be made in the 
 channel, its small excess of weight compared with that of the water, 
 would render it almost no impediment to the first vessel which 
 passed, and that would clear the channel for the next one, while the 
 first freshet in the river would doubtless entirely sweep it out. 
 
I 
 
 18 
 
 '■■HhA conHiderable portion of the sawdust which is thrown into 
 the stream will doubtless accumulate in the side bays of still water, 
 and Homotimos, perhaps, temporarily in parts of the channel where 
 previous obstructions have been produced by logs, brush, slabs, 
 leaves, sand, etc., but in these cases it will again bo removed by the 
 first freshet. 
 
 I have not examined the navigable channel of the Ottawa, with 
 reference to this particular question, and have therefore based my 
 opinion upon my observations for many years of the upper an(i 
 Lower Hudson; the Delaware and Susquehanna; the rivers in the 
 state of Maine, and those in some of the Western States, where very 
 large saw mills have been in use for many years. 
 
 ^ In all of these cases I have never observed, nor heard o^ com- 
 plaints made of any obstruction or impediment to the navigation 
 by vessels, or floats, from the deposition of sawdust. 
 
 The present investigation satisfactorily explains why no such 
 deposits or obstructions to the navigation of those rivers have oc^ 
 curred. 
 
 ■ f .t*i;r,M|^a«'8; •i.>;3. ,-'?« Respectfully yours, 
 
 Wm. J. Mc-ILPINE. 
 
 
 '.it 
 
 tf- 
 
 <.f*^«4ri:> 
 
 H. F, Bronson, Esq., I "f "' - ;ffo 
 
 i Ottawa, Canada. J 
 
 Sir, — I have examined the question, submitted by you, as to 
 whether there is any reason to apprehend the formation of obstruc- 
 tions to navigation, in the Ottawa Eivor, as the result of the deposi- 
 tion of the saw-dust made by the mills at and above the City of 
 Ottawa, when the same is cast into the river. 
 
 Before, and during the investigation, I conferred with the Hon. 
 W. J. McAlpine, with whom I have had the honor to be associated, 
 and with whom I consulted as to the line of investigation to be pur- 
 sued. The conclusions to which I have been led have been submit-- 
 ted to and discussed with Mv. McAlpine, who, I am happy to say. 
 entirely concurs with me, and who will so report to you. 
 
 In considering this as a purely engineering question, the follow-' 
 ing questions naturally present themselves : — 
 
 First, — What are the causes which induce the formation of bars 
 and obstructions in navigable and other streams? 
 
 Second, — What materials usually compose such bars and obstruC; 
 tions ? * 
 
6 
 
 Third, — What are the specific gravities of those materials ? And 
 
 Fourth, — What velocities of current are necessary to take up 
 and transport those materials to the point of tinal deposition in the 
 bar? 
 
 Having answered those several questions, it will next be neces- 
 sary to inquire in regard to the specific gravity of saturated pine 
 saw-dust, and the velocity of current necessary to take it up and 
 transport it. 'U;''(': ■ '".* i....^ :'-,i.i-:. •■;;;■'.■ 
 
 These questions will be considered In the order in which they 
 are stated. ■-■ ,-,'■*' •■'*" !:■■ , ■' ' ' •- ■". .;;; <■ ' a 
 
 Causes of the ForiuiTIon op Bars. ^ - '" '■ 
 
 When the velocity of the current in any etroam is sufficient to 
 enable the water to scour or abrode the materials composing the 
 bottom and sides therof, these materials will be taken up by the 
 moving water, held in suspension in it, and transported down 
 stream, until, by a widening or deepening of the channel, or both 
 combined, the section of the stream becomes so much enlarged, and 
 the velocity of the current so much reduced that the floating ma- 
 terial can no longer be held in suspension or transported. 
 
 When this occurs, a deposit takes place which continues to in- 
 crease so long at, the water, arriving at the point, continues to be 
 charged with the heavy material. In time, if this process be con- 
 tinued, the result is the formation of a bar, which, if the stream be 
 used for navigation purposes, may prove to be a serious obstruction, 
 and one requiring removal by artificial means. 
 
 In some streams the formation of bars is a continuous process; 
 in others, bars are only formed during freshets, when the velocity 
 of the current, ordinarily too low to effect a disturbance of the ma- 
 terial of the bed, becomes temporarily sufficient to take up and re- 
 move large quantities of this material to deeper and wider portions 
 of the stream further down. 
 
 ^ These deposits occur not only in the channel and in its immediate 
 vicinity, but also in eddies, near the margin, and in eddies formed 
 by artificial structures, such as bridge piers and abutments, which 
 serve not only to obstruct the free flow of the water, but to divert 
 it from its natural course. 
 
 Materials Deposited in Bars. 
 1 .e materials usually deposited in the formation of bars and 
 other obstructions to iiavigation are mud, coarse and fine sand and 
 gravel ; to which are sometimes added water-logged timber, chips, 
 
wir 
 
 and 
 
 I 
 
 f 
 
 sticks, leaven and other detrital matter. Generally, however, bars 
 are principally composed of mud, sand and gravel. 
 
 Specific Gravities op the Materials. 
 
 Before giving these it is well to note that the ultimate particles 
 of sand and gravel may be quartz, feldspar, mica or slate ; or these 
 materials may be all combined in the same specimen of sand or 
 gravel; Pebbles also of diiferent kinds may be mingled with gravel. 
 It will therefore be necessary to present the specific gravities of a 
 considerable number of substances in order to include all that may 
 be Ibund in a deposit of sand and gravel. ' 
 
 The following table gives the specific gravities of a sufficient 
 number of these materials, and includes also some others which have 
 been found in motion near the bottom of the Hudson Eiver. 
 
 *" " Material. . Bpcclflc Gravity. 
 
 Clay in bulk 1-93 
 
 Common soil, in bulk 1-98 
 
 Coal, bituminous 1.27 
 
 " anthracite 1-44 
 
 ' ' " " " 1-64 
 
 '^i ' Earth, loose 1.50 ^ • 
 
 '^'' Granite 2-62 *' ' 
 
 " 2-70 • * 
 
 Limestone 3- 18 'inul 
 
 ! Marble 2-70 
 
 V " 2-80 ;:. , 
 
 Mica 2-80 -^^ ,,< 
 
 Sand, in bulk 1.80 
 
 Slate 2.67 
 
 Stone, common 2-52 T ' 
 
 In regard to those materials in the above table designated as 
 "in bulk," such as clay, common soil, loose earth and sand, it is to 
 be'remarked that the ultimate particles, except such as are of vege- 
 table origin, are much heavier than is indicated by the tabular 
 numbers. The sand, for instance, being made up of quartz, feldspar, 
 mica and slate, whose specific gravities vary from, say 2.50 to 2.80, 
 we should not expect it to be disturbed by the same current which 
 would take up single particles o^ the same magnitude, whose specific 
 gravities were only 1.80, or eqial to that of sand in bulk. 
 

 % 
 
 Vblocitieb op Current required to take up and TRANCPonr . 
 
 Different Materials. , .i«qt;-.-ifh«| tp 
 
 Upon this subject there are many authorities. D'Aubui^eon, 
 an eminent French authority, says : — " When a proper relation is 
 established so that the channel contains all the water brought (1o"mi 
 by the river, in its great freshets, without injury, it is said to have 
 acquired stability, and the regime of the river is eatablisl>ed." 
 
 " The velocity of the regime is strictly related to lj|:^e ^pe|?i(49 pi' 
 •gather size of the substances which form its channel. ' r " 
 
 -- r «Du Baat has made some experiments upon this subject of 
 great interest. lie has taken different kinds of earth, sands and 
 Htones, which he placed in succession upon the bottom of a wooden 
 canal ; by inclining it differently he has varied the velocity of the 
 water passed through it, and has verified how much is necessary to 
 put each substance in motion, fle had for 
 
 Potter's clay U-264 ft. per second. 
 
 Finesand 0-5249 J', " 
 
 Gravel from the Seine, size of peas 0-6233 ' '-*- " 
 
 Pebbles from sea, one inch in diameter 2 •132 " " 
 
 Flint stones, size of hen's eggs , 3-281 " " 
 
 He then spread a bed of sand upon the bottom of the canal and 
 caused the water to run over it with a velocity of • 984 feet per 
 second." Under these conditions the particles of sand were found 
 to be moved forward at the rate of nineteen feet in twenty-four 
 hours. 
 
 The velocities given above are those which are just sufficient to 
 disturb the various materials ; higher velocities would be required 
 to promptly take up and carry off these matoi'ials. '»'^** 
 
 David Stevenson, C E., in his work on " Canal and Kiv Engi- 
 neering," p. 143. gives the following as the results of experiments 
 made by Bossut, Du Buat and others, on the siz,e of detrital particles 
 which streams flowing with different velocities are capable of carry- 
 
 0-25 ft. per 8econd=0-170 mile per hour will just begin to work on fine clay. 
 
 .0-50 
 
 
 067 
 100 
 
 << 
 a 
 
 (( 
 
 
 (( 
 
 ._.■•■■;% 
 
 200 
 
 a 
 
 (( 
 
 
 a- 00 
 
 t* 
 
 tt 
 
 % 
 
 
 
 
 = 0'34 do will lift fine sand. 
 
 = 0*46 do will lift sand as coar'^e as linseed. 
 
 = 0-68 do will sweep along fine gravel. 
 
 = 1-36 do will roll along rounded pebbles one 
 
 inch in diameter. 
 =2*045 do will sweep along slippery angular 
 
 stones, ATS of an eg,- 
 
Lewis Gordon, Eegius Professor of Civil Engineering and Me- 
 chanics in the University of Glasgow, in his synopsis of lectures on 
 Civil Engineering, p. 16, says : . < 
 
 " The relation between the velocity of current and the quality 
 of detritus ca^'ried along by rivers is illustrated by the following 
 facts:—" 
 
 Material Transported. Velocity of Strenm at Surface. 
 
 Fine clay and lime 0-6*7 ft. per second. 
 
 Fine sand 1-00 
 
 Eough sand 1-50 
 
 Very fine gravel... 2-00 
 
 Gravel 1 inch diameter 3-00 
 
 Gravel of 2 inches diameter. . . 5-00 
 
 Stones ^ cubic foot Y-OO 
 
 " 1 " 10-00 
 
 " 2 « 15-00 
 
 *« 10 to 15 cubic feet 36-00 
 
 u 
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 il 
 (I 
 II 
 u 
 
 « 
 
 u 
 II 
 (( 
 a 
 (( 
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 « 
 
 ■•Mill ,>. . 
 
 rv 
 
 m;i'^: 
 
 Prof. Julius Weisbach, in his ''Mechanics and Engineering," 
 Vol. 2, p. 156, says : 
 
 " A velocity of T to 8 inches per second is necessary to prevent 
 deposit of slime and growth of weeds, and IJ feet per second is 
 necessary to prevent deposit of sand. The maximum velocity of water 
 in canals depends on the nature of the channel's bed." 
 
 On a Slimy bed the velocity should no<, exceed 0-25 ft. 
 
 " Clay do do 
 
 " Sandy do do 
 
 " Gravelly do ...... do 
 
 " Shingle do ..... do 
 
 " Conglomerate do 
 
 " Hard stone do 
 
 This ai)i3lies to the mean velocity." 
 
 The above velocities are such as, according to this eminent 
 German authority, may be allowed without endangering the integ- 
 rity of the beds of canals (or rivers,) when those beds are composed 
 of the materials set opposite the several velocities respectively. 
 
 The velocities, generally, given in the preceding tables are 
 those which ai-e sufficient to disturb the condition of the bottom, and 
 ..1 time to pernanently change its character, by the slow removal 
 
 B 
 
 . 0-50 '• 
 . 100 " 
 . 2-00 " 
 . 4-00 « 
 . 5-00 " 
 .10-00 " 
 
10 
 
 W:i 
 
 of material from some points and its su bsequent deposition at otheri« ; 
 they are not such velocities as will produce sudden changes, by the 
 rapid removal of materials. In short, they are intended as guides 
 to the engineer, and indicate the limits of velocity, for the several 
 material^ beyond which the current should nover be permitted to 
 run in artificial channels. 
 
 Much valuable information bearing directly upon ths case in 
 hand, has been obtained from the charts of that portion of the 
 Hudson River, lying between the city of Troy and the village of 
 'Now Baltimore, embracing a distance of about 20 miles, and in- 
 cluding all that portion of the river where troublesome bius, and 
 other impediments to navigation occur. 
 
 These charts wore constructed from surveys made during the 
 yeai's 1867-68, under the direction of the U. S. Engineer Department, 
 and for the pm*pose of obtaining information upon which to base 
 plans for the permanent improvement of the navigation of the 
 river, by the removal of the then existing obstructions, and by the 
 adoption of measures to prevent the formation of like obstructions 
 
 in the future. ia-.^^'^ri^ul-x'it'-^Pi ;•?! .ri/iHll-ririW ^!l:li. f. -'i 
 
 During the progress of the survey, attention was naturally 
 directed to the velocity of the current of the river, and to the kind 
 and character of the materials which were being moved down 
 stream, at and near the bottom. ...• . ► 
 
 Careful observaiions were made for the purpose of procuring 
 reliable information upon these points. The velocity of the cur- 
 rent was ascertained at nearly one hundred diflierent points; and at 
 each of these points, an instrument, designated the " sand collector," 
 was sunk to the bottom, and aUowed to remain there fifteen 
 minutes, after which it was removed carefully and the quantity, 
 kind and character of the materials collected carefully noted. 
 
 The results of these examinations, the officer in charge of the 
 U. S. Engineer Office in Albany, has kindly permitted me to copy 
 from the charts in that office. 
 
 They are embraced in the following table : ^' "" • 
 
 
 .t'-- 
 
 
11 
 
 OBSERVATIONS WITH SAND COLLECTOR. 
 
 Velocity 
 
 per 
 Second. 
 
 Quarter 
 
 of 
 
 Tide. 
 
 1.67 feet 
 
 1.43 
 1.39 
 1.14 
 0.83 
 0.67 
 0.91 
 1.03 
 1.05 
 
 1.39 
 
 1.64 
 1.72 
 1.54 
 1.67 
 1.14 
 1.11 
 1.45 
 1.69 
 
 1.61' 
 1.59 
 
 1.82 
 1.79 
 
 1.61 
 1.67 
 1.82 
 1.3G 
 2.00 
 
 1.75 " 
 1,12 ". 
 
 0.94 
 1.67 
 
 1.61 
 
 2.08 
 
 (C 
 
 << 
 (( 
 cc 
 (( 
 << 
 (( 
 
 It 
 
 <( 
 ti 
 
 C( 
 (C 
 
 ef 
 (f 
 
 (C 
 
 e( 
 
 (C 
 
 2nd 
 
 « 
 
 « 
 (( 
 
 3rd 
 (( 
 
 (( 
 
 (< 
 
 4th 
 
 (C 
 
 <( 
 
 2nd 
 
 « 
 
 3rd 
 
 <( 
 
 (C 
 
 cc 
 
 4th 
 
 cc 
 ct 
 cc 
 
 3rd 
 
 ?nd 
 
 cc 
 
 3rd 
 
 2nd 
 
 .s 
 
 fl 
 a 
 o 
 
 02 
 
 9.3 feetl with 
 
 Wind. 
 
 10.3 
 13.2 
 11.6 
 13.6 
 12.8 
 11.0 
 11.2 
 10.2 
 
 9.3 
 
 8.0 
 
 10.0 
 
 12.2 
 
 8.1 
 
 10.0 
 
 9.8 
 
 8.1 
 
 9.4 
 
 8.2 
 8.6 
 
 7.9 
 9.6 
 
 8.7 
 8.7 
 7.4 
 8.7 
 20.8 
 
 19.0 
 18.6 
 
 10.4 
 12.5 
 
 9.8 
 12.4 
 
 C( 
 
 « 
 c< 
 c( 
 cc 
 cc 
 cc 
 
 C( 
 
 C( 
 (C 
 C( 
 
 cc 
 « 
 cc 
 c: 
 ti 
 
 ti 
 if 
 
 tt 
 it 
 
 ti 
 cc 
 cc 
 cc 
 tf 
 
 tt 
 tt 
 
 it 
 
 tt 
 it 
 tt 
 tt 
 
 2 with. 
 
 1 '•' 
 
 cc 
 
 Calm. 
 
 tt 
 tt 
 tt 
 tt 
 tt 
 tt 
 tt 
 It 
 
 tt 
 
 tc 
 
 cc 
 cc 
 
 (C 
 
 cc 
 cc 
 tt 
 tf 
 
 tt 
 
 tt 
 
 tt 
 tt 
 
 <* 
 
 ..^c. 
 
 Description of Deposit. 
 
 Very small quantity of sand and gravel 
 
 — largest, size of a pea. 
 Nothing. 
 
 A few pebbles ; largest, the size of a pea. 
 A few small pebbles. 
 Nothing. 
 Nothing. 
 
 A few small pebbles. 
 Nothing. 
 One small pebble and several pieces of 
 
 water-logged wood. 
 Small quantity of pebbles ; largest, 
 
 size of a grain of coffee. 
 A few small pebbles. 
 
 cc cc tt 
 
 Nothing. 
 
 Nothing. 
 
 Nothing. 1 
 
 Nothing. 
 
 A few grains of coarse sand . 
 
 Two cub. in. ofsand and gravel ; largest, 
 
 size of a coffee grain. 
 Small quantity of coarse sand and gravel 
 10 cubic inches coarse " " 
 
 3 " " of sand and gravel ; 
 
 largest, size of a coffee pod. 
 3 cubic ms. ofsand and gr ivel ; largest, 
 
 size of a pea. 
 Nothing. 
 
 2 cub. ins of fine sand. 
 Small quantity of fine sand. 
 Very small quantity of fine sand. 
 Considerable quantity of water-logged 
 
 pieces of wood, and a small quantity 
 
 of fine sand. 
 
 cc cc cc tC 
 
 Small quantity of very coarse sand, 
 
 and water-logged wood. 
 Nothing. 
 Small quantity of coarse sand and a 
 
 few small pebbles. 
 Coarse sand and small pieces of wood 
 
 and coal ; largest piece of coal 
 
 about the size of a grain of coffee. 
 Nothing. 
 
i]? 
 
 OBSERVATIONS WITH SAND COLLECTOR— Con^mMeei. 
 
 
 Velocity 
 
 Quarter 
 
 per 
 
 of 
 
 Second. 
 
 Tide. 
 
 to 
 
 a 
 
 c 
 o 
 
 1.80 feet 
 
 1.67 
 
 1.79 
 1.74 
 1.63 
 1.63 
 1.65 
 
 1.00 
 
 1.33 
 
 1.41 
 1.69 
 1.74 
 
 1.48 
 1.43 
 
 1.39 
 
 1.48 
 
 1.08 
 1.56 
 
 1.49 
 
 1.48 
 
 1.36 
 1.52 
 
 1.10 
 1.01 
 L.63 
 1.60 
 1.50 
 
 (C 
 
 (< 
 <( 
 (( 
 
 <( 
 
 (C 
 
 (( 
 (( 
 
 (( 
 
 (< 
 (( 
 (( 
 (( 
 <( 
 
 l8t 
 
 3rd 
 
 Ist 
 3rd 
 4th 
 
 l.)tofF'd 
 
 L. W.St 
 4th 
 
 (C 
 
 3rd 
 
 4th 
 
 14.8 
 11.4 
 
 10.7 
 12.4 
 11.2 
 10.0 
 12.5 
 
 10.4 
 
 11.4 
 
 8.8 
 
 7.7 
 
 16.4 
 
 L. W. St 
 4th 
 
 3rd 
 2nd 
 
 « 
 
 l8t 
 
 2nd 
 3rd 
 
 16.2 
 
 8.3 
 
 13.0 
 
 13.4 
 
 11.7 
 9.1 
 
 10.6 
 
 12-6 
 
 11.0 
 11.3 
 
 13.9 
 19.6 
 20.2 
 15.3 
 16.3 
 
 fee^ 
 
 
 
 (( 
 
 a 
 
 (( 
 <( 
 
 (C 
 
 Wind. 
 
 Calm. 
 
 (C 
 (C 
 
 <c 
 
 i .Description of Deposit. 
 
 'if 
 
 << 
 n 
 
 << 
 
 1 against 
 
 Calm. 
 « 
 
 ec 
 <( 
 
 (( 
 (( 
 
 Sjnall quantity of coarse sand and 
 pebbles ; largest, size and shape of 
 a 3 cent piece. 
 Coarse sand, pebbles and debris of 
 ., . various kinas ; largest pebble, size 
 ' of a pea. 
 Nothing. . ,.i,: i,.vi;, •-. "fKA 
 
 Nothing. -- ,. ' .. ,j fj 
 
 Coarse sand. •> ■ ,. ^u i 
 
 Very small quantity of fine sand. 
 Fine sand cmders, and coal ; largest 
 
 F)iece of coal, the size of an almond, 
 1 quantity of fine sand and pebbles, 
 
 largest pebble, the size of a coffee 
 
 gram. 
 Medium line sand and small pieces of 
 
 coal ; largest, size of a pea. 
 Coarse sand very small pieces of wood. 
 Fine sand. 
 Fine sand and small pieces of wood } 
 
 varying from 2i^ inches long down-. 
 
 wards. 
 Fine sand. 
 Coarse sand, coal and cinders ; largest. 
 
 .size of a pecan nut. 
 Medium fine sand and gravel : largest, 
 
 the size of a small pea. 
 Coarse sand and pebbles ; largest, size 
 
 of a grain of coffee. 
 Coarse sand. 
 Coarse sand and one pebble, the size of 
 
 $ of a pea. 
 Sand and gravel, largest the size of two 
 
 coffee grains. 
 Fine sand, water-logged chips and a few 
 
 small pebbles, the sizeof ^ ofapea.- 
 Very fine sand. 
 Fine pand and gravel ; largest, the size 
 
 of a spilt pea. 
 
 Verv fine sand. ^^^.^. ,,.-_ ^^ ^, ..^^,^^,,^.. 
 
 Nothing. 
 
 Medium fine sand. ft I 
 
 Coarse sand and Hmall pieces of wood. 
 2 cub. ins. of coarse sand and large 
 roi-i. proportion of small pieces of wood. 
 
OBSERVATIONS WITH SAND COLLECTOR— Continued. 
 
 Velocity 
 
 per 
 Second. 
 
 Quarter 
 
 of 
 
 Tide. 
 
 a 
 o 
 
 Wind. 
 
 Description of Deposit. 
 
 2.19 " 
 
 2.21 " 
 2.36 " 
 2.27 " 
 
 2.64 " 
 
 2.86 " 
 2.46 " 
 
 2.29 " 
 
 2.2G " 
 
 3rd 
 
 te 
 
 4th 
 »f 
 
 (( 
 
 <c 
 
 (C 
 
 It 
 
 L. W. St 
 
 18.0 feet 
 20.3 " 
 
 is.'i* «' 
 
 12.1 " 
 9.8 " 
 
 Calm. 
 (( 
 
 (t 
 
 te 
 
 (t 
 a 
 
 ti 
 
 (C 
 
 6| cub. ins. of coarse sand and small 
 
 pieces of wood. 
 6 cub. ins. " " « 
 45 cub. ins. « " « 
 16 " " of fine sand and one small 
 
 shell. 
 252 cub. ins. of coarse sand and piecee 
 ' of wood. 
 
 30 cub. ins. of medium fine sand. 
 18 cub. ins. offine sand and small pieces 
 
 of wood. 
 216 cub. ins. of medium fine sand, and 
 
 small pieces of wood. 
 54 cub. ins. of medium fine sand, and a 
 
 few pieces of wood. 
 
 The results given in the preceding table, are given in their 
 regular order, commencing just below the State Dam in the city of 
 Troy, and terminating at the village of New Baltimore. 
 
 An examination of this table shows that the observed velocities 
 varied from 0*67 of a foot per second as a minimum to 2-86 feet per 
 second as a maximum, or from about half a mile to about two miles 
 per hour ; that the materials found moving at the bottom were fine 
 and coarse sand, gi-ayel, pebbles from the size of a quarter of a pea 
 to the size of an almond, shells, coal, cinders and pieces of water- 
 logged wood; that small pebbles were found moving where the 
 velocity of the current was as low as 0*91 of a foot per second ; that 
 the lowest velocity of current found to cai'ry pieces of water- logged 
 wood was 1-05 of a foot per second; that in a current of 1-39 feet 
 ])er second, pebbles as large as peas were found moving ; that 1-36 
 feet per second was the lowest velocity of current in which fine sand 
 was found, but that in no single instance, within the 20 miles, was a 
 particle of saw-dust observed among the materials brought up from, 
 the bottom. 
 
ii'.j 
 
 !ii 
 
 »ii 
 
 fin 
 
 In this connection, it is important to note that, upon a small 
 
 stream emptying into the Hudson at Albany, and near its mouth, 
 
 there is an extensive saw-mill; that there is a large saw-mill on 
 Green Island, at the west end of the State Dam and opposite to the 
 
 City of Troy ; and that at both of these mills the saw-dust is cast 
 
 into the river. , - 
 
 It is also important to note that at Fort Edward, Sandy Hill, 
 Glen's Falls and Warrensburgh, each of which points are located 
 upon the Hudson Eiver, at distances varying from 40 to 75 miles 
 above the City of Troy, the manufacture of lumber is, and has been 
 for nearly a century, carried on, the annual product for the last ten 
 years being estimated by experts at from 150,000,000 to 200,000,000 
 feet B. M. 
 
 At all these points the saw-dust, together with large quantities 
 of slabs and edgings, are and have been from the beginning cast into 
 the river. 
 
 !»?»* At Glen's Falls water is taken Irom the Hudson Kiver to feed 
 the Champlain Canal, and in dry seasons nearly the entire flow of the 
 river is thus diverted. 
 
 Dilligent inquiry has been made of gentlemen engaged in the 
 lumber business, of canal officials, of persons who for many yeai*s 
 were charged with and gave their personal attention to keeping the 
 Champlain and the Hudson Eiver free frcm obstructions to naviga- 
 tion, and of persons engaged in navigating the river and in trans- 
 porting merchandize theron ; but I have failed to learn that bars or 
 other obstructions to navigation, composed wholly or in part of saw- 
 dust, have ever been formed either in the Champlain Canal or in the 
 channel of the Hudson Eiver. 
 
 In order to find an explanation of the real or apparent absence 
 of saw-dust in the Hudson Eiver, I have been compelled to resort to 
 experiment, there being no Engineering authorities upon subject of 
 the specific gravity of saturated saw-dust, or upon the velocitr of 
 current necessary to take it up and transport it. 
 
 i Specipio Gravity of Pine. 
 
 My experiments have been wholly confined to white pine wood, 
 in blocks and in the condition of saw-dust, both dry and saturated 
 with water. I have thus limited myself ibr the reason that white 
 pine constitutes the principal part, if not the entire product, at the 
 the City of Ottawa, and for the reason that upon the Hudson, for 
 many years, little else than pine lumber was manufactured. 
 
 ■■■m 
 
 4 
 
15 
 
 Blocks of white pine, unseasoned, have, according to different 
 authorities, specific gravities varying from 0-46 to 0-65, depending in 
 some degree upon the locality in which it is grown. 
 
 According to my experiments, the specific gravity of white pine 
 in different conditions as to dryness is as follows : — 
 
 Spcclflo Gravity. > 
 
 > Unseasoned 0-466 
 
 Partly seasoned 0-418 
 
 Dry O'SSY 
 
 It would therefore seem that this wi>od, when reduced to the 
 condition of saw-dust as well as when in mass, should float upon the 
 surface of the water; but our obsei'vations generally, as well as 
 observations made for the specific purpose of ascertaining ita 
 behavior in water, teach us that when unseasoned coarse pine saw- 
 dust is placed in still water, a large portion will immediately sink, 
 and that within three days the whole will sink to the bottom. 
 
 This i'i generally attributed to the fact that the finely divided 
 wood readily absorbs water and becomes " water-logged." But it is 
 to be borne in mind that since a particle of saw-dust when thoroughly 
 water-soaked is heavier than water, and since the absorbed water can 
 be no more dense than an equivalent volume of water at any other 
 point in the mass, the ultimate fibre of the wood must be heavier 
 than water, else the water-soaked particle wo'ild not sink. Thia 
 appears to be the case, also, from the fact that some of the particles 
 sink immediately, while the wood in its normal condition invariably 
 floats on the surface of the water. ; 
 
 I explain this apparent anomaly by saying rhat those particles 
 which sink immediately are such as have been condensed by the 
 action of the saw in cutting them from the wood, and thus reduced 
 to less than half their original volume when in the natural state. 
 
 Having satisfied ourselves, then, that the fibre of pine wood is 
 heavier than water, it becomes necessary to ascertain precisely how 
 much heavier than water it is; for it is upon this fact, together with 
 the specific gravity of the dry wood (in the block), that we mufet 
 base our conclusions as to the probable behavior of saturated saw- 
 dust in water, as compared with that of the usual constituents of 
 bars. 
 
 Careful experiment, undertaken for the expirees purpose of deter- 
 mining this point, shows that the specific gravity of the fibre of pine 
 wood is 1.2624. or that the fibre is about 26 per cent, heavier than 
 water. But the saturated particle of saw-dust, consisting as it does 
 
1^ 
 
 Ih, 
 
 of a bundle of these fibres with the interstices filled with water, has 
 a still different specific gravity. "' 
 
 To ascertain this approximately, we take thoroughly seasoned 
 white pine wood, assume that the mass of wood is made up of a 
 definite volume of woody fibre of known specific gravity, and that 
 sufficient void space is inclosed in the mass to reduce its specific 
 gravity as a whole to what has been determined for it, viz.: 0.337. 
 
 Since, then, the specific gravity of the mass is only 0.337, and 
 that of the fibre 1-2624, it follows that only fMh = 0-2(J7 of the 
 wood is made up of woody fibre, while the remainder, 1-00 — 0-267 = 
 0-733 of the entire volume is void space, which is capable of receiving 
 and retaining water. We have, then, in saturated saw-dust a com- 
 pound of 0-267 of woody fibre, specific gravity 1-2624, and 0-733 of 
 water, specific gravity 1-00. 
 
 Tlie specific gi-avity of the compound, or of the saturated particle 
 of sawdust, is determinad as follows : — .,r^i .t^i 
 
 0-733x1-00 = 0-733 
 :. ^, 0-267x1-26 = 0-33642 
 
 m,;A? i^'' 
 
 Thus 
 
 '"f '^tj 
 
 :r^)- 
 
 
 1-000 1-06942 i^^ fetMsia? 
 
 it appears that, the volume of the wood remaining 
 imchai.j^ed during the process of absorption, the specific gravity of 
 the saturated particle will be 1-069, or about 7 per cent, heavier than 
 that of water. 
 
 But as there is always an enlargement of volume during absorp- 
 tion, the saturated particle will contain a larger proportion of water 
 than we have used, and hence the actual specific gravity of the satu- 
 rated article will be even less than 1.069. 
 
 In my opinion 1.05 will more nearly represent the specific 
 gravity sought ; indeed this indicated by certain weights, observed 
 for other purposes, during the progi'ess of my experiments. 
 
 Whatever may be the precise specific gravity of the saturated 
 particle, the fact is established that it is only very slightly in excess 
 of that of water; and hence that the velocity of current required to 
 lift and transport it after it has once sunk must be very slight. 
 
 Velocity of Current Eequired. 
 
 For the purpose of ascertaining what velocity of current will 
 
 take up and remove deposits of saturated saw-dust, a wooden trough 
 
 was procured, which was four feet long, three inches wide, and three 
 
 inches deep. Three inches from one end of this trough a bulkhead 
 
 was placed, forming a compartment of 27 cubic inches capacity, for 
 the reception of the water. 
 
The bulkhead was perforated with a large number of small 
 holes, designated to allow the water to flow through into the trough 
 without producing undue agitation or disturbance of the water 
 flowing below. At the other end of the trough a weir was placed, 
 which was finally regulated to such a height as to just discharge the 
 water flowing in the trough when the requisite velocity had been 
 obtained. The height of this weir, as it was finally adjusted, was one 
 inch, and it extended entirely across the end of the trough. - 
 
 The depth of the flowing stream in the trough was generally 
 about an inch and a-half, the precise depth being, however, measured 
 during the progress of each experi lent. 
 
 The trough having been '/aref uUy levcslled, water was admitted 
 into the upper compartment tiom a hose attached to a hydrant, and 
 the flow was adjusted by a cock at the hydrant. 
 
 Thoroughly saturated coarse white pine saw-dust was then 
 scattered into the trou^a in such quantity as to entirely cover the 
 bottom, where it remained at rest. The flow of water was then 
 gradually increased until the particles of saw-dust manifested a 
 decided tendency to rise and move down stream to and over the 
 weir. The rate of the flow was such that about a teacup-full of the 
 saturated saw-dust was removed in from twenty to thirty minutes. 
 
 It is proper to remark, however, that the particles were moved 
 slowly, at a velocity considerably less than that finally established 
 for the experiments. 
 
 • 
 
 During the progress of the experiments the water discharged 
 over the weir was repeatedly collected and weighed, and the section 
 of the flowing stream meatured. 
 
 From data thus obtained the following velocities have been 
 calculated for coarse saw-dust: — 
 
 Ist Observation, velocity = 0-290 ft. per second. 
 2nd « « = 0-283 " « « 
 
 3rd " " = 0-280 " " " 
 
 4th '< « = 0-281 " '< « 
 
 From which we obtain a mean of 0-2836 foot per second, or less 
 than one-fifth of a mile per hour. 
 
 At the conclusion of these observations, a very small accumular 
 tion of saw-dust remained just above the weir, which, by the way, 
 was slowly disappearing. 
 
18 
 
 The How was then gradually increased to such an extent that 
 the accumulation referred to was taken up and entirely removed in 
 about one minute. • 'i j t» ^f/ 
 
 Under this condition of things the velocity of the current was 
 found 10 be only 0382 of a foot per second, or about one-fourth of a 
 mile per hour. 
 
 At this point, then, we have established the following facts, viz. : 
 That a current velocity considerably loss than one-fifth of a mile per 
 hour suffices to take up and transport slowly coarse saturated pine 
 saw-dust; that a velocity of one-fifth of a mile per hour produces a 
 very decided movement down stream of such particles; and that a 
 velocity of one-fourth of a mile per hour suffices for their entire and 
 instantaneous removal. 
 
 Experiments were also made with very fine saturated saw-dust, 
 and it was found that the decided movement of the particles was 
 effected by a current velocity of 0-246 of a foot per second ; also that 
 the instantaneous removal of the very small accumulation just above 
 the weir was accomplished by a cuiicnt of 0-288 foot per second, or 
 very nearly a quarter of a mile per hour. . . - ,■ ■■ .. ,; (^,i , . ;, 
 
 Thus it appears that with saturated saw-dust — as with gravel 
 stones, pebbles of different sizes, and other materials of nearly the 
 Bamo specific gravity — the velocity required to move the particles 
 varies with the size of those particles; in other words, the larger the 
 volume of the particle, the greater the velocity of current required 
 to transport it. 
 
 The accuracy of the determination in regai'd to coarse saw-dust 
 was verified by other experiments with that material, as the result 
 of which, the velocity which promptly moved the particles was found 
 to be 0-290 of a foot per second. , , . , 
 
 In the case of particles of materials of different specific gravi- 
 ties but of the same size, it is clear that the force or velocity of 
 current required to move them w^ill vary with their specific gravities, 
 and hence we can readily understand why a current which carries 
 pieces of w^^ater-logged wood may only be able to carry coarse sand 
 or fine gravel stones, and why — as in the case of the observations on 
 the Hudson Eiver — both these materials, together with fine sand, 
 may be found in motion at the bottom, in the same place and at the 
 same time. ).■*,■ m, •:■•-■• jw ^.?-v'r.-,'r.;r,, ,,',,,■,,,,.,. j^.:^,,s.,jt_j.j. -j^j,j ,;r,.^T. 
 
 The absence of bars or accumulations of saw-dust in the channel 
 of the Hudson Eiver is therefore readily accounted for. it will be 
 
10 
 
 romcmbered that the mininmm velocity of current found by tlio 
 U. S. Enyincera, between tlio head of navigation and the village of 
 New Baltimore, was 'iiore than double that which we have found to 
 be capable of transporting saturated saw-duwt (0-67 to 0-28). 
 
 From the lumber manufacturing region to the head of naviga- 
 tion the fall in the river is over 100 feet. The velocity of the current 
 must therefore be greater than that upon that portion of the riv ©r 
 embraced in the Government surveys. 
 
 We should expect, then, that the saw-dust cast into the river 
 would be carried down the river by the current, while the total 
 absence of any accumulation of saw-dust in the Champlain Canal 
 proves that whatever refuse from the mills at and above Glen's 
 Falls finds its way into it, through the Glen's Falls Feeder, must be 
 carried down by its current; and be ultimately discharged, with the 
 waters of the canal, into the Hudson E'ver at Troy and Albany, 
 whence it is finally carried to the sea. 
 
 That there is nothing inconsistent with this theory, in the 
 immense quantity of saw-dust annually produced on the Hudson 
 River, may be readily shown. 
 
 Taking the annual production of lumber upon the Hudson 
 River at 160,000,000 feet, and assuming, as we are authorized to do, 
 that the average thickness of this lumber will not exceed IJ inches, 
 and also taking the thickness of material cut out by the saw at i\ of 
 an inch, it appears that a cubic foot of solid wood is reduced to the 
 condition of saw-dust for every 80 feet of lumber sawed. 
 
 In a year, then, the aggregate volume ot wood reduced to saw- 
 dust will be ^ 'OW"" ^ = 2,000,000 cubic feet. At 30 pounds to the 
 cubic loot, this volume of pine wood will weigh 60,000,000 pounds, 
 or 30,000 tons. 
 
 The water shed of the Hudson River, above Fort Edward, has 
 been estimated by the State Engineers at 1,374,500 acres. A fair 
 estimate of the rain-fall collected into and carried off by the river is 
 a volume equivalent to a depth of 20 inches of water on the entire 
 water shed each year. This gives for the armual flow of the ri"er 
 at Fort Edward, 99,788,700,000 cubic feet, whence it follows that 
 the ratio of the volume of wood reduced to saw-dust, to the volume 
 of water flowing in the river, is 1 to 49,894. 
 
 Assuming, now, that the saw-dust is uniformly distributed 
 throughout the water, let us — in order to make the comparison more 
 intelligible — see what volume of wood will be contained in a barrel 
 
20 
 
 : ! 
 
 ! 
 
 I : 
 
 •80 
 
 of water. The computation shows that In a barrel of 31^ gallons 
 there will he just j'sV^ of a cubic inch of wood. 
 
 By weight, the relation between the wood and water, is p,s 1 to 
 *^^; or as 1 to 1)9,788, in which, for convenience, wo take the 
 specific gravity of the wood at 0-5; which is sufficiently near the 
 truth for our purpose. 
 
 Now, in a wine gallon of water there are about G4,051 grains ; 
 whence it follows that, in case of the aswumod uniform distribution 
 of the saw-dust, there would be, in a wine gallon of the river water 
 at Fort Edward, only UUh = 0-641 of a grain of saw-dust. 
 
 At Troy, below the junction of the Mohawk Hiver, the flow of 
 the river is fully three times as great us it is at Fort Edward. Here 
 then, the relative quantity of saw-dust is onl}'^ one-third as great as 
 at Fort Edward ; or 0-214 of a grain to tlie gallon. Farther down 
 the river, as at Poughkeepsie, the flow of the river is fully four times 
 as great as at Fort Edward ; and, as a consequence of the continued 
 dilution, the quantity of saw dust at this point would be only 0-lGO 
 of a grain to the gallon. 
 
 Specimens of water from the river at Poughkeepsie, taken fi'om 
 a point 60 feet from the surface and 10 feet I'rom the bottom, have 
 been recently analyzed by Prof. Chandler, of Columbia College. 
 Prof. Chandler's analysis show that a wine gallon of this water con- 
 tained 1,239 grains of organic and volatile matter. Croton water 
 contained only 0-67 of a grain. 
 
 Hudson Eiver water contained 0-373 of a grain of organic carbon 
 to the gallon ; croton water only 0-287 of a grain. s 
 
 The excess of organic and carbonaceous matter in the Hudson 
 Eiver water is accounted for by the saw-dus\., which our experiments, 
 together with the current observations of the United States Engi- 
 neers show, may be, and undoubtedly is, carried not only to that 
 point, but still further onward to the sea. 
 
 We can readily understand, also, in view of the very small 
 quantity of saw-dust — as compared with the flow of the river — how 
 it may be floated downwai'd with the water without attracting atten- 
 tion, even from those directly charged with the duty of ascertaining 
 what materials were hold in suspension in the water, at and near the 
 bottom, and were being carried down by the current. 
 
 Another important fact worthy of note, as showing that, in the 
 vicinity of Albany at least, the bare and accumulations which ob- 
 struct navigation are entirely free from saw-dust, is, that the sand 
 
21 
 
 ")sU 
 
 ufiod in the masonry of the Erie Cnnnl, between Albany and Cohoew 
 as well m that uned in the masonry of the foundations of the now 
 State Capitol, was taken from those bars on account of its extreme 
 purity and freedom from organic matter. 
 
 1 have boon thus particular in the examination of the Hudson 
 River in reference to the question of t-iaw-dust do])OHits, lor the rea- 
 son that it is, in many rcspcctH, a parallel case to that of the Ottawa 
 River; and hence, that the oxj)orience on the former would servo, 
 in some degree, to indicate what may be expected to occur on the 
 latter. 
 
 Both are largo rivers, and upon lx)th, large quantities cf lumber 
 are manufuctrred. 
 
 ITpon the Hudson, the bulk of the pine was manufactured into 
 lumber man;, years ago; while now, the lumber made is piincipally 
 hemlock and spruce; upon the Ottawa, the bulk of the lumber thus 
 far made, has been white pine. 
 
 The quantities of lumber manufactured, annually, on the two 
 rivers, is about the same; the product upon the Hudson being pro- 
 bably somewhat in excess of that upon the Ottawa. ' ' - *• ■ " ^ - 
 
 In the length of time, however, during which lumbering opera- 
 tions have been carried on upon the two rivers, there is a marked 
 dift'erenco. Upon the Hudson these operations have been carried on 
 for nearly a century ; and, from the best information attainable, it is 
 probable that, during that time, an a\ orage of nearly 20,000 tons of 
 saw-dust have been cast into the river annually, besides large quan- 
 tities of slabs and edgings ; so that the aggregate quantity of refuse 
 from the mills thus cast into the river may be safely put at 2,000,000 
 tons. :;■'' V"?!i!.-^ 
 
 As saw-dust this would occupy a space of about 400,000,000 
 cubic feet ; equivalent to a cubical pile, 1,000 feet square at its base, 
 and 400 feet deep. 
 
 Uj)on the Ottawa, on the contrary, extensive lumbering operor 
 tions wore only commenced at a comparatively recent period. 
 
 Again, the saw mills upon the Hudson are more than 200 miles 
 from its mouth ; while upon the Ottawa they are less than half that 
 distance; both are for the most pai-t comparatively sluggish streams. 
 
 Thus, it appears that the very question under consideration, 
 has been subjected, upon the Hudson River, to a very severe practi- 
 cal test, covering a period of nearly a century ; and yet, that saw- 
 dust obstructions, in the navigable channel, or in the canals fed from 
 this river, have never been known. 
 
22 
 
 The Penobscot Eiver in MLvine. *f?m t 
 
 w. 
 
 \^ 
 
 Sworn statements have been obtained of persons who have been 
 engaged upon, ^nd are acquainted with the Penobscot Eiver, in the 
 Statfj of Maine, which runs through a pine timber region, upon which 
 very extensive lumbi ng operations have been conducted for many 
 yGarS; and into the waters of which vast quantities of sawdust and 
 edgings are and have been cast. 
 
 These statements show that accumulations of saw-dust alone, in 
 the channel of that liver, have never been known; and that no 
 injuiy, impediment or obstruction to its navigation, has ever result- 
 ed from the casting of saw-dust into it. 
 
 Conclusion. 
 
 In view of my experimental rejults, together with the facts 
 observed by the United States Engineers upon the Hudson Eiver, 
 and in view of the experience of lumbermen and navigators upon ' 
 the Hudson and Ptrobscot rivers, I have formed the following 
 opinions, viz : — 
 
 ,4 That saturated pine saw-dust will not be permanently deposited 
 in water when the velocity of the current exceeds 0-25 of a foot per 
 second, or one sixth of a mile per hour; that wat«r logged chi's 
 may be deposited, when the velocity of the current is less than 1-00 
 foot per second, or about two-thirds of a mile per hour ; that saw- 
 dust may accumulate in eddies and in still water, or where the velocity 
 of the current is permanently less than 0-20 to 0'25 of a foot per 
 second ; that bars of sand and saw-dust combined will not be formed 
 under any circumstances ; for the reason that when the velocity of 
 the current is diminished so as to permit the deposit of sand, it is 
 still more than twice as great as is necessary to hold and transport 
 saturated saw-dust, and hence, that saw-dust will not accumulate, or 
 be permanently deposited in rivers where sand bars occur, unless 
 there exist expansions of the river, below sucS sand bars, sufficient 
 to make a cross section more than double that at the site of the bar; 
 that if, in low water, saw-dust should accumulate in small quantities, 
 the accoUerated current of the first freshet would take it up and 
 sweep it down stream, and finally ; that, as it is extremely impro- 
 bable that the minimum freshet velocity, in the Ottawa Eiver, ever 
 falls below 0-25 of a foot per second, there is no reason to anticipate 
 tlie formation of permanent or troublesome bars or accumulations of 
 saw-dust in that river. 
 

 23 
 
 *? This opinion may be modiiied or strengthened when more 
 definite and precise information shall have been obtained, in relation 
 to the magnitude of the Ottawa River, its water shed, and other 
 characteristics. , , 
 
 . . -V • ,. , 1 am, Sir, 
 
 ! ^, i 
 
 ''!'*(•• j'ti 
 
 ^J" 
 
 
 , I-,. ^.u:u , Very respectfully, 
 
 J). M. GREENE, 
 
 Civil JUngineer 
 
 ■■U 
 
 CoC: ■ - ' > ■ 
 
 11. F. Bronson, Esq., " " !....; 
 
 Dear Sir,— Since my arrival in Ottawa I have been put in pos- 
 sion of such information in regard to the magnitude, character, and 
 habits of the Ottawa River as will enable me to form more definite 
 and decided opinions as to the possible effect upon navigation, which 
 may be produced by casting saw-dust into the river at this point. 
 
 I learn from a paper, signed A. J. Russell, that the extent of 
 territory drained by the Ottawa and its tributaries, above the City 
 of Ottawa, is 43,000 square miles ; that between the City of Ottawa 
 and Grenville the territory drained is 19,000 square miles; and, that 
 4,000 square miles additional territory is drained below Grenville. 
 
 The total territory drained by the Ottawa and its tributaries, is 
 then as follows : — 
 
 ^ Above the City of Ottawa 43,000 sq. miles, j ] ',[ "Tj ," 
 
 " Grenville b'2,000 " / * 
 
 " Montreal 66,000 « 
 
 From the same source I learn that, " by the Report to the 
 Canaxiian Legislature, of T. C. Clarke, Esq., C. E., of his survey for 
 the Ottawa Canal Navigation, the mean discharge of the Ottawa (by 
 a series of observations) at Grenville is 85,000 cubic feet per second ;" 
 that at low water, the discharge is 35,000 cubic feet per second, and 
 that at high water the discharge is 150,000 cubic feet per second ; 
 also, that the annual precipitation of rain and snow in this part of the 
 Do-- inion may be safely taken at 40 inches of water. 
 
 That the foregoing data are sufficiently reliable for our purpose; 
 or, that the territory drained and the rain-fall are equally in error, 
 in the same direction, (which is extremely improbable,) is indicated 
 by the relation which the mf an flow of the river bears to the rain- 
 fall. 
 
r 
 
 'it 
 
 i 
 
 it 
 
 24 
 
 85,000 cubic f<?et of snow for a year, represents a volume of 
 water equivalent to 18.2 inches deep, over the entire drainage terri- 
 tory above Grenville ; or — '~j^ = 45J per cent of the rain-fall. 
 
 This being, substantially, the usual estimate of engijieers for the 
 volume of water flowing iu streams of this character, I feel war- 
 ranted in assuming that the information furnishod by Mr. Eussell is 
 reliable. 
 
 It appears then, that the Ottawa Eiver, at the City of Ottawa, 
 
 is , n ^j gnA " = 20 timeii "^ large as the Hudson at Fort Edward, 
 1,3/4,500 ° ' 
 
 and 6f times as large as the Hudson at Troy. 
 
 Comparing the Ottawa at Grenville with the Hudson at Troy, 
 we find that the former is ten times as large as the latter. 
 
 It follov, s, then — since the minimum ob^ierved velocity at that 
 point in the Hudson was 2^ times that required to transport satur- 
 ated saw-dust — that no deposit can occur in the channel of the Ottawa, 
 unless some point can be found where the cross-section of the river 
 is 10x2^ = 25 times as large as that of the Hudson at Troy. Those 
 who are acquainted with both rivers will scarcely admit the exist- 
 ence of such a point on the Ottawa. 
 
 In the absence of precise data as to the width and depth of the 
 Hudson at Troy, I have been compelled to resort to the determina- 
 tion of velocities, at various points upon the Ottawa, between the 
 Cities of Ottawa and Montreal, For this purpose I have hcd re- 
 course to the maps, constructed from the surveys of the Ottawa 
 River, made in 1856-7-8, unde. the direction of W. Shanly, C. E.. 
 facilities for the examination of N.hich were kindly furnishod by 
 
 , Deputy Commissioner of Public Works. 
 
 These maps show, that between the City of Ottawa and the 
 head of the lake above Grenville, the maximum width of the river is 
 4,000 feet; and that the minimum width is about 1,400 feot; while 
 "he maximum dej-th of water recorded was 30 feet. 
 
 The maximum width of the lake referred to is about 7,600 feet, 
 and the maximum depth of water recorded, 30 feet. 
 
 a point four miles above Grenville, the width is 3,200 feet, 
 and the niaxium depth,30 feet. 
 
 Three miles above Grenville the width is 1,800 feet, and the 
 maximum depth, 30 feet. 
 
 Two miles above Grenville, the width is 2,400 feet, and the maxi- 
 mum depth, 30 feet. 
 
maxr 
 
 One mile above Grrcnville, the widtli at the time of the survey 
 
 was 1,200 feet, and the maximum depth, 2G feet. 
 
 At trrenviile, the width was 1,600 feet and the maximum depth, 
 30 feet. 
 
 Just above Grenville, the maximum width, between banks, is 
 
 about 8,000 feet, and here, in consequence of the extreme width of 
 the river in high water, togetlier with an abrupt change in tha direc- 
 tion of the channel a large "sand shoal" has been formed, which 
 was bare at the time of the survey, Tlie existence of other "sand 
 shoals " is indicated at points further down the river. 
 
 In a distance of four miles below Grenville, the maximum width 
 is about 3,600 feet; the depth, however, is not indicated. 1 shall 
 assume that it is 30 feet, or over. 
 
 Below the Chute de Elondeau, in a di<stance of five miles, the 
 maximum v/idth is about 3,000 feet, and the depth will be taken at 
 30 feet or over. 
 
 The widest portion of the river, between the Cities of Ottawa 
 and Montreal, shown upon the map, is at Lake of Two Mountains, 
 where the width is about 10,500 feet, and where I again assume the 
 depth to be 30 feet or over. — (Mr. Clark puts it vl from 13 to 30 
 feet.) 
 
 A ctti'eful examination of all the depths recorded upon the maps 
 and reference to the Beports of Messrs. Clark and Shanly satisfy me 
 that, although the depths of water sometimes exceed 30 feet, the 
 excess" cannot be great. In order, howevet*, to cover any possible 
 excess over 30 feet, I shall assume, in computing the sections of the 
 river at the various points where the widths have been given, that 
 the depths given and assumed are the overage depths of the sections. 
 
 It will be seen that while I shall thus obtain sectional areas 
 lai'gely in excess of the true areas, where the soundings were 
 frequent and the maximum depth of water definitely ascertained, I 
 shall provide for a large margin for safety wherever there is any 
 uncertainty as to the maximum depth of water. In this manner I 
 shall obtain velocities which, if they var^^ in either direction, will iall 
 belov/ the actual velocities. 
 
 ApproxIxAiate Sections and Velocities at Low Water. 
 
 By the process indicated above, I find the maximum cross 
 section and the minimum mean velocity between the City of Ottawa 
 and thj head of Lake Original to be 120,000 sqiuire feet, and 0-30 of 
 a foot per second respectively, while the miiumum section and the 
 maximum velocity are 42,000 square feet and 0-83 of a foot per 
 second respectively. 
 
 D . 
 
36 
 
 1 
 
 In Lake Orignal, the maximum section and the minimum 
 velocity are 228,000 square feet and 0154 of a foot per second, 
 respectively. 
 
 At a point four miles above Grenville, the section and velocity 
 are 96,000 square feet and 0-37 of a foot per second, respectively. 
 
 Three miles above Grenville, the section and velocity are 54,000 
 square feet and 0-65 of a foot per second, respectively. 
 
 Two miles above Grenville, the section and velocity are 72,000 
 square feet and 0.50 of a foot per second, respectively. 
 
 One mile above Grenville, the section and velocity are 31,200 
 squai-e feet and 1-12 of a foot per second, respectively. 
 
 At Grenville, the section and '. elocity are 48.000 square feet and 
 0.73 of a foot per second, respectively. ^ ^ m ^ .; -^ ^ 
 
 In a distance of four miles elow Grenville, the maximum sec- 
 tion and the minimum velocity are 108,000 square feet and 0.32 of 
 a foot per second, respectively. 
 
 In a distance of five miles below the Chute a Blondeau, the 
 maximum section and the mm i mum velocity are 90,000 square feet 
 and 0.39 of a foot per second, respectively. - .r 
 
 In Lake of Two Mountains, the maximum section and the 
 minimum velocity, by the process adopted, appear to be 315,000 
 square feet and 0.11 of a foot per second, respectively. Eut here. 
 as in Lake Orignal, oui section, judging from Mr. Clarke's statement 
 in regard to depth of water and the natural formation of the bed in 
 such cases, is much larger than the actual section and our velocity 
 as much too small. Half the section found, and double the velocity, 
 would, in my judgment, more nearly accord with the actual section 
 and velocity. 
 
 However, wo will let the results stand as we have found them, 
 and proceed to the determination of the approximate velocities at 
 high water. 
 
 Approximate Velocities at High Water. 
 
 The volume of water flowing in the Ottawa Eiver at Gn.iville 
 at high water is about four times as great as that flowing in time of 
 low water ; more acurately, it is WAV = •1-29 times as great. 
 
 Taking, now, the average depth between the City of Ottawa and 
 Grenville at high water at 50 per cent, greater than that at low 
 water, the sections will rJso be 50 per cent, greater in high than they 
 are in low water. , 
 
 The minimum velocity, then, between Ottawa and Grenville in 
 high water will be||^ xO-37 = 1-06 feet per second, a velocity suf- 
 
ficient to carry small gravel stones, and four times as great as that 
 required to take up and transport saturated pine saw-dust. 
 
 In the widest portion of Lake Orignal, the velocity wdl be 
 
 4-29 
 1-5" 
 
 X 0154 = 0-44 of a foot per second, or more than 50 per cent, more 
 than is required to move saw-dust, and sufficient to move fine sand. 
 f Belo,w Grenville, taking the depth at high water at 40 per cent, 
 greater than that at low water, the minimum velocity in a distance of 
 four miles will ^e f|^ >< 0-32 = 0-98 of a foot per second. 
 
 Below the Chute a Blonde lu, the minimum velocity in a distance 
 of five miles will be ^- x 0-39 = 1-20 feet per second. 
 
 In the Ijake of Two mountains, taking the depth at high water 
 at 30 per cent, greater than that at low water, the minimum velocity 
 will be *-^^ X 0-1 1 = 0-34 of a foot per second, or more than 20 per 
 cent, greater than that required to move saturated pine saw-dust. 
 
 That the velocities which we have thus deduced are none too 
 high, but that they ai"e, in all probability, much too low, especially in 
 Lake Orignal and in Lake of Two Mountains, is evinced by the fact 
 that ''sand shoals'^ occur below these points which could not have 
 been formed had not the velocities above them been at least 0-50 to 
 0-60 of a foot per second, or sufficient to have taken up and trans- 
 ported the sand to the point of its final deposition. 
 
 The current, which was capable of doing this, was still able, 
 after a reduction of- the velocity which permitted the deposit of the 
 sand, to sweep the saw-dust forward and into the more rapid currents 
 below, which would hurr;^ it on with varying speed until the waters 
 of the Ottawa mingle with those of the St. Lawrence at Montreal. 
 
 Thus it appears, that woile it is barely possible (though alto- 
 gether improbable,) that in extreme low water, slight deposits of 
 saw-dust may accumulate in the deep water, in Lake Orignal, and 
 in Lake of Two Mountains, the first succeeding high water would 
 inevitably sweep such. possible accumulations forward to the St. 
 Lawrence. 
 
 As a matter of curiosity suppose we admit that no saw-dust is 
 carried below Grenville, or that it is wholly deposited in Lake Orig- 
 nal, and ascertain, if possible, what the result would be at the end of 
 a century. 
 
 Taking the annual manufacture of lumber at the City of Ottawa 
 at 160,000,000 feet B. M., and assuming as wo have already shown 
 that a cubic foot of solid wood is reduced to the condition of saw- 
 dust for every 80 feet of lumber sawn, we get for the volume of 
 wood annually reduced to the condition of saw-dust, ^ ' ^ oo^o^qqq .d — 
 
2,000,000 cubic feot. TIuh, as saw-dist, would make 0,000,000 euhic 
 feet annually. Then in a century the accumulation would bo GOO,- 
 000,000 cubic foet. 
 
 The length of Lake Orignal is a /Out six miles; if then we as- 
 sume that this mass of saw-dust be spread over a portion of the river 
 bed six miles long, and 4,000 feet average width, the depth of the 
 
 accumulation would be only ta-t^'— p-k„57^ = 4.74 feet deep, and 
 
 '' 4000 X 6 X 5280 ^ 
 
 would reduce the depth from 30 feet to 25.26 feet. If the width of 
 the accumulation be Jissumed at only 2,000 feet (maximum width of 
 the lake is 7,609 feet,) the depth of the accumulation would bo 9.48 
 feet, and the effective depth of the channel would be reduced from 30 
 to 20.52 teet. 
 
 .^ If this process of accumulation were to go on, the section of the 
 stream would be gradually reduced and the velocity increased until, 
 at length, it would become suffiicently great to carry down not only 
 §aw-dust but heavier material as well. 
 
 A channel, 2,000 feet wide, and having an average depth of 17^ 
 feet is required to discharge the minimum flow of the river at Gren- 
 ville, with a mean velocity of 1.00 loot per second. If the average 
 depth remained constant, and the width be reducied to 1,000 feet, the 
 requisite mean velocity would be 2-00 feet por second. Thus in this 
 view of the ease, it appears that a serious obstruction of the naviga- 
 tion of the river, as the result of the floating and subsequent deposi- 
 tion of loose material, would be next to impossible, — except at such 
 points as, on account of great width of section, afforded the requisite 
 cross-section with a depth less than that required for the purposes of 
 navigation. 
 
 Samples of material, six in number, taken from the shoal places 
 between the City of Ottawa and Grenvillo, have been shown me. 
 These materials are wholly composed of pure clean sand of different 
 degrees of tineness. Not the slightest indication of the presence of 
 saw-dust can be detected in any of the samples, even when examined 
 under a glass. 
 
 As the result of this further investigation, together with the 
 examination which I have made of the materials taken from the 
 shoals in the Ottawa Eiver, the opinions which I expressed in my 
 former commimication are not only confirmed, but are very mater- 
 irtll}^ strengthened ; and I now feel no hesitation in expressing the 
 opinion that saw-dust obstructions have not thus far been formed in 
 the channel of the Ottawa River, and that there is no reason what- 
 ever to apprehend the formation of such obstructions in the future. 
 
 I am. Sir, 
 
 Very respectfully, 
 
 D. M. GREENE, 
 
 Civil Engineer. 
 Ottawa, Ont., March 10th, 1871.