316 New Scale for the Mountain Barometer —Optics. 
life? Did it terminate life by destroying the electrical powers 
of the brain? I hope some of your readers will, through the 
medium of your valuable work, favour me with some remarks on 
these cases, aid replies to my queries. Iam, sir, your consfant 
Reader, } R. R. 
Piceadilly, Oct. 17, 1817. 
NEW SCALE FOR THE MOUNTAIN BAROMETER. 
Professor Bertoneelli of Verona has contrived an ingenious 
method of adapting a graduated measure to the common scale 
of the barometer, to indicate the height of mountains without the 
necessity of calculating for the different degrees of temperature, 
&c. To the common scale he adapts a corresponding one, di- 
viding the inches into 100, placing his zero at mean pressure, 
and ascending both ways in numeration from that point. This 
scale is surmounted by a brass revolving cylinder on which are 
graved four different series of lines; one perpendicular divided 
like the preceding; another of ten diverging lines which ascend 
the whole length of the cylinder, and the rationale of which the 
Professor has not stated ;—these lines are again partially inter~ 
sected by two series of four lines diverging at right angles from 
the point of zero, and designed to indicate the correction for 
difference of temperature. The whole cylinder revolves by means 
of a screw, and acts in conjunction with the counter scale of the 
barometer ; it is accompanied by a vernier, which is commanded 
by two or three screws to the point of correction; while this 
vernier is also to act in correspondence with a common nonius 
placed on the inch scale opposed to the surface of the mercury, 
This complex machine Professor Bertoncelli calls an Ipsographie 
seale, which nevertheless has still to be read off and calculated 
by the aid of logarithms. If he could find a metal which would 
not contract with cold, then his series of screws and tangent lines 
might be useful; and if logarithms were more familiar than com- 
mon addition or subtraction, this instrument might prove of 
much general utility. 
OPTICS. 
A very interesting case has just oceurred, of a person born | 
blind being restored to sight by the means of a surgical opera- — 
tion:— A native of Burdwan, of the age of eighteen, was lately 
sent by his family to Dr.Luxmore, of whose success in the removal 
of the cataract they had heard by public report. The operation 
was performed on the 26th, and in six days he began to see and - 
distinguish objects. After the celebrated case of Dr. Chesel- 
den’s patient, whose sensations have been so minutely and phi-— 
losophically laid before the public, it can hardly be expected that 
any discovery regarding the origin of our ideas of figure, distance, 
er quantity, could be extracted from the observation of an ig- 
norant 
