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 Avith 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 po\ver. But, notwithstanding this 

 practical difficulty, which, by the Avay, is not in the cases of 

 alcohol and Avood 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 then production equal quantities of caloric." 



Dr. Todd exhibited a fragment of an ancient Pentateuch 

 roll, written on leather, in the square HebreAV character, and 

 containing a portion of the book of Leviticus, from chap. xx. 

 19, to xxii. 23. It Avas 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 Avith scarcely 

 any divisions betAveen the words, but the character or style of 

 the Avriting 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 JeAvs 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 



