LS 
British hiepibiins eb the Adéancomentof Science. 297 
force over te earth’s. eusoee. The American observations. were 
made with needles inelosed.i in a vacuum apparatus, which Prof. 
B. had devised, with the. view of avoiding some of the anomalies 
occasionally experienced by other. observers. .They were made 
with extreme care, and were remarkable for minute attention to. 
all those SRS OMSIAD CAR which eopdnee, to the accuracy of the 
results. 
The oasnaiaey ae Mr. Snow -Hatris’s Report 1 of Meteorole- 
gical Observations made at Plymouth. Mr. E. Hodgkinson 
gave several’ observations made the last year on temperature in 
deep mines. in Cheshire and Lancashire, a full report of which 
he hoped to offer at the next meeting. Mr. Russell described an 
- apparatus for showing the connexion of magnetism with the wind, 
invented by Mr. Watt. 
Section B. Chemistry and. sinieeiiaets : 
Dr. Thomas Thomson on Native Diarseniate of Bead: Die 
ring the meeting of the. Association at Liverpool, a collection of 
minerals from Alston Moor was exposed for sale. Among them 
was one labelled, “ Vanadiate of lead from Caldbeck Fell.” It was 
in botryoidal concretions on quartz. Several-of these nodules, 
had, under thé microscope; the aspect of cylinders. Color, honey- 
yellow, like that of arseniate of lead, but lighter ‘and much less 
translucent. Lustre, resinous, and, more brilliant than that -of 
vanadiate of lead. Does not scratch’ calcareous spar, but scratches 
gypsum with great ease. Gravity, 7.272: that of vanadiate of 
lead is only 6.663. Before the blowpipe on platinum foil, it melts 
into a transparent globule, which on cooling, assumes nearly its 
original appearance. On charcoal, it gives out abundant arsenical 
fumes, and leaves globules a —_ see Two analyses by 
- 
lating, 68S apie gOS SORES 28 gage 
Lead FE Se are ne een 
Atsenic acid,’ > SP ste 18.20 
Protoxide of lead, - -- ~ - = - 70.14 
Peroxide of iron, - .- = te WA... 
Volatile matter, - 7< a ears 1.00" 
3 100.10 
Mr. Séanian cortirunicated observations: on the Constitution 
of the Commercial Carbonate of Ammonia. ~The results.of his 
Vou. SAV No. 2. 38 
~ 
