275 
‘* The mere inspection of these numbers is sufficient to show 
that Mr. Ainger is in error, or that by substituting for water, 
wood spirit, alcohol, or ether, the same moving force will be 
obtained, and with a great saving of fuel. With wood spirit, 
about two-thirds, with alcohol, about three-fourths, and with 
ether, somewhat less than half the caloric required by water 
will suffice. 
‘ To the use, however, of such liquids there are obvious ob- 
jections. Their cost is considerable compared to that of wa- 
ter, and as they evolve at atmospheric temperatures vapours 
of a considerable elastic force, they will, from imperfect con- 
densation, resist the motion of the piston, and thus give rise 
to an appreciable loss of power. But, notwithstanding this 
practical difficulty, which, by the way, is not in the cases of 
alcohol and wood spirit one of a very formidable nature, the 
theoretic conclusion is no less certain, that equal volumes of the 
vapours of different liquids, formed at their respective boiling 
points under the pressure of a single atmosphere, do not re- 
quire for their production equal quantities of caloric.” 
Dr. Todd exhibited a fragment of an ancient Pentateuch 
roll, written on leather, in the square Hebrew character, and 
containing a portion of the book of Leviticus, from chap. xx. 
19, to xxii. 23. It was found by Ford Leathley, Esq., in the 
tomb said to be Absalom’s tomb, at Jerusalem, December 7th, 
1842. 
It is written without points or accents, and with scarcely 
any divisions between the words, but the character or style of 
the writing does not indicate a very remote antiquity. It is 
probably a MS. of the fourteenth century, and is evidently a 
fragment of one of the smaller Pentateuch rolls, written for 
the use of the synagogue. It is customary with the Jews to 
bury such rolls with their dead, when they had become injured 
or worn with use, and also if, upon examination, they had 
been found to contain any error, which could not, consistently 
