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A great achievement in engineering
Nov., ~9ol.]
Males a z d Comments.
369
invention, providing as it does such an excellent method of operating series are lamps from the same generators which supply incandescent light and power, recommends to Elihu Thomson the award of the John Scott Legacy Premium and Medal, for his invention of the Constant Current Alternating Are Light Transformer. Adopted at the stated meeting of the Committee on Science and the Arts, held Wednesday, February 6, I9OI. J O H N B I R K I N B I N E , President. W M . H , W A H L , .Secretary.
Countersigned by Louis E. LEvv, C/mirman &mini/tee oJ~ 5"ciettce and the Arts. A G R E A T ACHIEVEMt~)NT IN ENGINF, ERING. T h e near completion of the new Delaware Breakwater, below Philadelphia, has been the occasion of a noteworthy statement from General Gillespie, chief of t h e Corps of Engineers of the United States Army, which we find in the c o l u m n s of the Philadelphia Public Ledger of August 29th , and the subs t a n c e of which we here condense. T h e old Delaware Breakwater is about one mile tong, contains 1,231,587 t o n s of stone, was seventy years (I828 to I898 ) under construction, cost about ~2,8o7,coo , and created a limited and shallow harbor of refuge, now used by s m a l l coasting and fishing vessels. In buildi,~g it the greatest amount of stone d e p o s i t e d in any one year was about 32,ooo tons. T h e new breakwater, designed in ~892, is about I'5 miles long, covers an area o f 552 acres, with m i n i m u m low-water depth of 3° feet, besides 237 acres w i t h 24 feet depth ; contains 1,464,4m toils of stone, which have been placed in p o s i t i o n in forty.four working months, the average per month being 32,300 tons, the m a x i m u m per m o n t h 62,7t9 tons, and the maximum year's work 45%460 tons. The work has thus been done about twenty-five times as rapidly as t h a t of the old breakwater. As to its cost, a direct comparison based upon its l e n g t h would not be fair. A better measurement is found in the circums t a n c e that in I892 a commission of engineers, basing its ealeulationsupon the e x p e r i e n c e gained in the building of the old breakwater, estimated the probable cost of the new one at $4,665,ooo ; whereas, it will be fully completed in N o v e m b e r next at a cost of about $2,239,334 , or slightly less than half the estimate. T h i s surprising result has been partly due to the very low price ($i.18~) per t o n at which, by t h e use of powerful machinery at both breakwater and quarry, the contractors have been able to put the rock in place ; but it is also largely the result of t h e great saving of at least 5oo,ooo tons in t h e amount of stone required, which has been effected by the new method of construction e m p l o y e d . Without going into a detailed description of this method, we may VOL. CLII.
NO. 9 xI.
24
37 °
Wales a n d Comments.
[J. F. 1.,
say t h a t it consists essentially in a d o p t i n g for t h e submerged portion of the b r e a k w a t e r a cross-section determined by t h e action of t h e sea itself, instead of a m u c h flatter slope, such as was previously supposed (without experim e n t a l reason) to be necessary. Lieutenant-Colonel Charles W. Raymond, t h e e n g i n e e r in charge, is entitled to the credit of h a v i n g proposed this bold innovation, secured for it, by his a r g u m e n t s a n d e x p e r i m e n t a l proofs, the approval o f t h e Board of U n i t e d States Engineers, a n d supervised its e x e c u tion with vigilance a n d intelligence. I n t h e words of General Gillespie the work is " a m o n u m e n t to his efficiency a n d skill as an e n g i n e e r . " During t h e progress of its construction t h e new Delaware Breakwater has been visited by m a n y engineers and has been watched w i t h great interest, as certain~ if successful, to m a r k a memorable advance in the methods of h a r b o r engineering. Thus far t h e m i n n t e s t observations have failed to detect the least sign of weakness or inadequacy in t h e novel submarine section employed. F o r the local conditions t h e r e is no doubt t h a t t h e plan is successful. W h e t h e r it can be employed, and how it would have to be modified for other localities a n d conditions remains to be determined. T h e t h e o r y of i t - - n a m e l y , t h a t in any locality t h e sea itself should b e allowed to d e t e r m i n e the s u b m e r g e d section for a breakwater, or, in o t h e r words, t h a t the talus of the b r o k e n stone should b e t h a t w h i c h the sea has been f o u n d t o form, and thereafter not to d i s t u r b - - s e e m s to be universally applicable. At all events, no great structures of this class will be u n d e r t a k e n hereafter in t h e civilized world w i t h o u t careful consideration of this new American precedent.--Engineerbzg and 3lining Journal. RIVER PROFILES. An interesting and valuable publication of t h e D e p a r t m e n t of Hydrogr a p h y of t h e United States Geological Survey on t h e " P r o f i l e s of Rivers in t h e U n i t e d S t a t e s , " by H e n r y Gannet, has just been published, and is n o w available for distribution. It embodies w i t h i n ioo pages t h e leading facts of about 15o of t h e most i m p o r t a n t rivers a n d streams of t h e country, noting t h e i r length, drainage area, t h e location of water power in t h e i r course, their peculiarities of flow a n d t h e nature of t h e i r drainage basins. T h e rivers selected are those which are t h e largest in size and bear most directly upon t h e varied interests of t h e country, such as t h e Connecticut, Hudson, S n s q u e h a n n a , ~ Ohio, Potomac, Mississippi, Missouri, Platte, Colorado, Sacramento, Columbia a n d others. T h e figures for the tables showing h e i g h t above sea level a n d fall per mile were collected from various sources. Some were obtained from the reports of t h e Chief ]~ngineer of t h e United States Army, some from railroad companies w h e n t h e i r lines cross t h e stream, a n d some from t h e atlas sheets of t h e U n i t e d States Geological Survey. I n t h e case of such rivers as the Connecticut, Susquehanna, Mississippi a n d Colorado, where t h e s u r r o u n d i n g c o u n t r y is in part or whole of peculiar p h y s i o g r a p h i c interest, very excellent a n d vivid descriptions of its leading physical characteristics are given, w h i c h add to t h e interest and render it valuable from a n educational s t a n d p o i n t in geographic a n d physiographic instruction. T h e p a m p h l e t is t h e result of m u c h careful work, and is the first a t t e m p t to collect and compile this information in its present form. W.
Males a z d Comments.
369
invention, providing as it does such an excellent method of operating series are lamps from the same generators which supply incandescent light and power, recommends to Elihu Thomson the award of the John Scott Legacy Premium and Medal, for his invention of the Constant Current Alternating Are Light Transformer. Adopted at the stated meeting of the Committee on Science and the Arts, held Wednesday, February 6, I9OI. J O H N B I R K I N B I N E , President. W M . H , W A H L , .Secretary.
Countersigned by Louis E. LEvv, C/mirman &mini/tee oJ~ 5"ciettce and the Arts. A G R E A T ACHIEVEMt~)NT IN ENGINF, ERING. T h e near completion of the new Delaware Breakwater, below Philadelphia, has been the occasion of a noteworthy statement from General Gillespie, chief of t h e Corps of Engineers of the United States Army, which we find in the c o l u m n s of the Philadelphia Public Ledger of August 29th , and the subs t a n c e of which we here condense. T h e old Delaware Breakwater is about one mile tong, contains 1,231,587 t o n s of stone, was seventy years (I828 to I898 ) under construction, cost about ~2,8o7,coo , and created a limited and shallow harbor of refuge, now used by s m a l l coasting and fishing vessels. In buildi,~g it the greatest amount of stone d e p o s i t e d in any one year was about 32,ooo tons. T h e new breakwater, designed in ~892, is about I'5 miles long, covers an area o f 552 acres, with m i n i m u m low-water depth of 3° feet, besides 237 acres w i t h 24 feet depth ; contains 1,464,4m toils of stone, which have been placed in p o s i t i o n in forty.four working months, the average per month being 32,300 tons, the m a x i m u m per m o n t h 62,7t9 tons, and the maximum year's work 45%460 tons. The work has thus been done about twenty-five times as rapidly as t h a t of the old breakwater. As to its cost, a direct comparison based upon its l e n g t h would not be fair. A better measurement is found in the circums t a n c e that in I892 a commission of engineers, basing its ealeulationsupon the e x p e r i e n c e gained in the building of the old breakwater, estimated the probable cost of the new one at $4,665,ooo ; whereas, it will be fully completed in N o v e m b e r next at a cost of about $2,239,334 , or slightly less than half the estimate. T h i s surprising result has been partly due to the very low price ($i.18~) per t o n at which, by t h e use of powerful machinery at both breakwater and quarry, the contractors have been able to put the rock in place ; but it is also largely the result of t h e great saving of at least 5oo,ooo tons in t h e amount of stone required, which has been effected by the new method of construction e m p l o y e d . Without going into a detailed description of this method, we may VOL. CLII.
NO. 9 xI.
24
37 °
Wales a n d Comments.
[J. F. 1.,
say t h a t it consists essentially in a d o p t i n g for t h e submerged portion of the b r e a k w a t e r a cross-section determined by t h e action of t h e sea itself, instead of a m u c h flatter slope, such as was previously supposed (without experim e n t a l reason) to be necessary. Lieutenant-Colonel Charles W. Raymond, t h e e n g i n e e r in charge, is entitled to the credit of h a v i n g proposed this bold innovation, secured for it, by his a r g u m e n t s a n d e x p e r i m e n t a l proofs, the approval o f t h e Board of U n i t e d States Engineers, a n d supervised its e x e c u tion with vigilance a n d intelligence. I n t h e words of General Gillespie the work is " a m o n u m e n t to his efficiency a n d skill as an e n g i n e e r . " During t h e progress of its construction t h e new Delaware Breakwater has been visited by m a n y engineers and has been watched w i t h great interest, as certain~ if successful, to m a r k a memorable advance in the methods of h a r b o r engineering. Thus far t h e m i n n t e s t observations have failed to detect the least sign of weakness or inadequacy in t h e novel submarine section employed. F o r the local conditions t h e r e is no doubt t h a t t h e plan is successful. W h e t h e r it can be employed, and how it would have to be modified for other localities a n d conditions remains to be determined. T h e t h e o r y of i t - - n a m e l y , t h a t in any locality t h e sea itself should b e allowed to d e t e r m i n e the s u b m e r g e d section for a breakwater, or, in o t h e r words, t h a t the talus of the b r o k e n stone should b e t h a t w h i c h the sea has been f o u n d t o form, and thereafter not to d i s t u r b - - s e e m s to be universally applicable. At all events, no great structures of this class will be u n d e r t a k e n hereafter in t h e civilized world w i t h o u t careful consideration of this new American precedent.--Engineerbzg and 3lining Journal. RIVER PROFILES. An interesting and valuable publication of t h e D e p a r t m e n t of Hydrogr a p h y of t h e United States Geological Survey on t h e " P r o f i l e s of Rivers in t h e U n i t e d S t a t e s , " by H e n r y Gannet, has just been published, and is n o w available for distribution. It embodies w i t h i n ioo pages t h e leading facts of about 15o of t h e most i m p o r t a n t rivers a n d streams of t h e country, noting t h e i r length, drainage area, t h e location of water power in t h e i r course, their peculiarities of flow a n d t h e nature of t h e i r drainage basins. T h e rivers selected are those which are t h e largest in size and bear most directly upon t h e varied interests of t h e country, such as t h e Connecticut, Hudson, S n s q u e h a n n a , ~ Ohio, Potomac, Mississippi, Missouri, Platte, Colorado, Sacramento, Columbia a n d others. T h e figures for the tables showing h e i g h t above sea level a n d fall per mile were collected from various sources. Some were obtained from the reports of t h e Chief ]~ngineer of t h e United States Army, some from railroad companies w h e n t h e i r lines cross t h e stream, a n d some from t h e atlas sheets of t h e U n i t e d States Geological Survey. I n t h e case of such rivers as the Connecticut, Susquehanna, Mississippi a n d Colorado, where t h e s u r r o u n d i n g c o u n t r y is in part or whole of peculiar p h y s i o g r a p h i c interest, very excellent a n d vivid descriptions of its leading physical characteristics are given, w h i c h add to t h e interest and render it valuable from a n educational s t a n d p o i n t in geographic a n d physiographic instruction. T h e p a m p h l e t is t h e result of m u c h careful work, and is the first a t t e m p t to collect and compile this information in its present form. W.