ON THE SMALL SCREW GAUGE. 469 
DIMENSIONS SPECIFIED. 
yee . 4:1 mm. = ‘16241 inch. 
A) Dae bp = CAMS, 555 
B 2°5 >» = 09682 ,, 
b 924); = Ofane 5, 
C 1:2 = 04724 ,, 
c 39 = TOBSES vy 
Value in Millimetres Value in Inches 
Screws Gos dh ike Pa Be ad Ty \ — | 
Bios./8; 7, 18 | Nominal | Observed | Difference | Nominal | Observed | Difference } 
| | 
3 fae 4-1 41023 | +0:0023 0716142 0716151 + 0:00009 
al? 3°224 3:2304 | +0:0064 | 012693 | 012718 | +0:00025 | 
74 Bis 2:5 2°5048 | +0:0048 0:09843 009862 +0:00019 | 
: hibits 1:924 1:9273 | +0°0033 007575 0:07588 +0°00013 
13 [KORE 1:2 12015 | +0°0015 0:04724 0:04730 | +0:00006 | 
pe... sty -yO48 =| +0:0048 0:03543 0:03562 +0:00019 
(Signed) H. J. CHANEY, 
July 10, 1899. 
On the Erection of Alexander IIT. Bridge in Paris. 
By M. AMEDEE ALBY. 
[Ordered by the General Committee to be printed in extenso. | 
Tr will be observed, on consulting a plan of the Exhibition of 1900, 
that Alexander III. bridge is situated on the line of the Great Avenue 
which will connect the Champs-Elysées with the Esplanade des Invalides. 
Like the Palaces of Fine Arts along the same Avenue, it will outlast the 
Exhibition, and perpetuate the remembrance of it by a durable embellish- 
ment of Paris. -Adsthetical considerations have therefore been of great 
importance in the plans which the engineers have prepared ; the technical 
details are also somewhat unusual and interesting in several respects, 
though they are not to be recommended for an economical solution of the 
problem of bridging a river about 500 feet wide. 
The first condition which the engineers attended to was not to injure 
in any way the scenery of the Seine on either side of ‘ Pont de la Concorde ;’ 
it was obvious at once that the low-arched form of bridge was the only 
acceptable one in these circumstances. 
Two other facts had to be borne in mind : these are, preservation of 
the view of Les Invalides, and absolute symmetry of the plans. It was 
considered of the utmost importance that there should be a possibility of 
seeing over the bridge the whole monument of Les Invalides from the 
Champs-Elysées. 
The decision of the authorities of the Exhibition of 1900 concerning 
this view of Les Invalides had been already successfully enforced in the year 
1828 by the Municipal Council of Paris, when they obtained the demolition 
of a suspension bridge constructed on the very site of the new bridge by 
the well-known engineer Navier, who had purposely gone to England to 
study the Norhamford and Menai suspension bridges. The presence of 
the columns of the suspension bridge was considered as an intolerable 
obstruction to the view of Les Invalides. 
The Palace of Industry (now demolished) was situated between the 
Champs-Elysées and the Esplanade des Invalides ; hence during about 
eee, 
