TRANSACTIONS OF THE SECTIONS. 27: 
On a New Marine and Mountain Barometer. By W. Symons, F.C.S. 
The barometer shown is a modification of the portable standard siphon-baro- 
meter introduced by the author a few months since, and described in various pe~. 
riodicals at the time. It is an adaptation of Gay-Lussac’s; but instead of having 
a vernier and scale to each tube of the siphon, an internal continuous metal tube 
is adjusted by a rack to the surface of the mercury in the short limb of the siphon, 
and the barometer is then read off in the usual way by a vernier and scale attached 
to the top of this internal tube, thus avoiding the double reading and necessary 
calculation of Gay-Lussac’s. There is, also, a very simple but effectual method of 
making the barometer portable by means of a leather plug on a steel wire, attached to 
asmall handle at the side; by shifting this handle about one-fourth of an inch, the 
flow of mercury is completely stopped. Marine barometers, as generally con- 
structed, haye been fractured by sudden concussions, as by firing a large gun; this 
arises, no doubt, from the necessity of fixing the tube firmly into the cistern. In 
the barometer shown this is obviated, as the tube need not be rigidly fixed, but 
may be supported in any point by elastic material, without deranging the accuracy 
of the instrument. 
On a Maximum Thermometer with a New Index. By W. Sxmons, F.C.S. 
Although there are two well-known and ingenious arrangements for maximum 
thermometers without indices, yet the constant demand for thermometers with in- 
dices shows at least a popular preference for them. There are, however, certain 
objections to those most generally in use. Steel not only corrodes, but its specific 
gravity is too great, Graphite has been much used, and if it be pure, it appears 
to answer every purpose ; but occasionally there exist in it impurities which ap- 
pear to corrode the mercury and soil the tube, The author has made a great 
number of experiments on the subject, and thinks he has now succeeded in 
making a composition, the basis of which is clay, which fully answers the pur- 
ose; for the sake of distinction, as it partakes somewhat of the character of stone, 
e has named it “lithite.” A considerable number of these thermometers have 
now been distributed, and as yet there has been no failure. 
On the Result of Reductions of Curves obtained from the Self-recording 
Electrometer at Kew. By Professor W. Tuomson, 7.2.8, 
The author said, that all the photographs up to last March had been reduced to 
numbers, and the monthly averages taken. Each month shows a maximum in the 
morning, sometimes from 7 to 9 A.M., and another in the evening, from 8 to 10 p.m. 
There are pretty decided indications of an afternoon maximum, and another in the 
small hours after midnight, but the irregularities are too great to allow any conclu- 
sion to be drawn from a mere inspection of the monthly averages. He intended to 
calculate three terms, if not more, of the harmonic series for each month, and thus 
be able to judge whether the observations show any consistence in a third term 
(which alone would give four maxima and four minima), or a first term (which 
alone would give one maximum and one minimum in the twenty-four hours), 
There is a very decided winter maximum and summer minimum on the daily 
ayerages. That for January is more than double of that for July. This part of 
the subject will also require much labour to work it out. In the reductions 
hitherto made he had included negatives with positives, and all the sums have 
been “algebraic” (i, e. with the negative terms subtracted). Very important 
results with reference to meteorology will, no doubt, be obtained by examining 
the negative indications separately ; and, again, by taking daily and monthly ave- 
rages of the jfine-weather readings alone. This part of the subject he had not been 
able to attack at all yet. Nor had he yet been able to go through a comparison of 
the amounts of effect with wind in different quarters. 
