157 
rrangement of the apparatus made use of in the experiments 
a nd the dimensions of the beams referred to. 
The beams experimented on were eighty-nine in number, 
and were cast by Mr. Mabon, at the Ardwick Iron Works, 
Manchester, from iron of the following- descriptions : — 
One charge of the cupola consisted of 
12 cwt. Goldendale, Staffordshire. 
12 ,, Lane End, ,, 
12 ,, Ormesby, Yorkshire. 
12 ,, Blair, Scotch. 
12 ,, Calder, „ 
All No. 3 hot blast iron. 
12 ,, scrap. 
The beams were cast on their sides, and were a very good 
sample of workmanship. 
The section of each beam was of the form recommended 
by Professor Hodgkinson, and upon which his formulae were 
based ; the total depth of the beam in the centre was 24;^ 
inches, and at the ends 20 inches; the bottom flange was 
15 inches wide, and 2^ inches thick ; the vertical part of the 
beam was l^inch thick; and the top flange was inches 
wide, and 1^ inch thick; the total length of the beam was 
34 feet 6 inches, and the distance between the supports w'as 
30 feet 9 inches ; the weight of the beam was 3 tons 
8 cwt. 1 qr. 
One of the beams was tested up to the breaking weight 
with the following results : — 
Tons. Cwt. Inch. 
With a load in the centre of 31 8 the deflection was .87. 
„ „ 42 16 „ 2.00. 
„ „ 46 12 „ 2.25. 
„ „ 50 8 „ 2.56. 
„ „ 54 4 „ 2.70. 
,, ,, 58 0 the beam broke, 
the ends springing back from each other 2 feet 3 inches, the 
fracture indicating a good sound casting. 
