284 Miscellaneous Intelligence. 
Liga only 80 lbs. The cost of 1 cwt. of coal is under 9d. ; the cost of 
1 cwt. of zinc is 216d. ‘Therefore, under the most perfect coo 
atl power must be nearly 25 times more expensive than 
e author proceeded to show that it was almost gn 
to be an impossibility ever to reach even this, owing, in the first place, 
os we rate with which the force diminishes through space. As t 
n of a great many experiments on a large variety of magnets, - 
diferent Aa and modes of construction, the following result W 
given 
Magnet and armature in contact, lifting force . . 220 |b. 
Sg lg ia nt sty of an inch. . 90°6 
pas 5 [74 tis ‘ i 50°7 
Z5 ‘ ‘ 
» 66 6s oe 6 : 7" 50°1 
6s oe 
=e . 40°5 
Thos at -onesfifieth of an inch distance four-Gfths of the power are 
his 
r rather 
ricily, acting in oeeetiee to me. bencai current by which ihe 
induc 
‘ Biehie de is nat all these. results, MP. 
ta iis disposed to. regard clectromugnetio ef as immpeaction 
ny account , he conceives, U0 
than ae am power; a 
Vv ae Atheneum.) 
ante, Jr ( of the 
dinary pum r.. Varl rley has a conti : 
dfe, and one puble-actingy barrel. he piston- 
‘the « motion eet ae the cy linder oscillates from it 
Da Maxine Biv 
