CONTENTS. 
On the Purification of Plating... ee ee ee 68 
A Method for ascertaining Latitude ino Time by means of 
Two known Stars “.. °.. abe) SSRI i J Rd 
A List of about 280 Mines of PSE with Zinc, Man- 
ganese, Copper, Iron, Fluor, Barytes, Sc. im and near ta 
Derbyshire .. .. ve ‘rs 106 
Rejoinder to the Rev. C. I. Siniy th’s Repl yy On Modes of 
Tuning Keyed Instruments; (see vol. xxxvi. p. 435.) 111 
On Oriental Bexoars 0. us ose ve ew 
On the Beats of Mr. Hawkes’s Douxeave, or common System 
of Twelve mystical, Notes 1... 2, \jouuR “\ansimhees ake Bae 
Communication on Water-Pressure Engines .. «+. 129 
On the Orbits of the newly discovered Planets .. 131 
Description of a Burning Mirror, ly means of which we 
may reflect and fix on any Object, whether at Rest or in 
Motion, the solar bei im as neh a Quantity as we 
plese: les vie eae Bek ci ie esis AL baby 
A List of about 700 oo and Eminences in and near to 
Derbyshire, with the Stratum which occupies the Top of 
each, and other Particulars,—and the Answers received, 
to Inquiries in our last Volume, respecting Mr. Michell 
and Mr. Tofield’s Geological Manuscripts, &c. i62 
On Tuning Musical Instruments .. «+ «. «+ 185 
On De Luc’s Electric Column’. .. 2. « .197,424 
Memoir on the Connexion which exists between the Oxidation 
of the Metals, and their Capacity of Saturation for the 
ACIS, «orn Voinnet bee dik: ane ye chee) staweee 
A concise Description of Schogicg ys peo tg im ‘euniae 
sey, with some bah on the nes of its Chaly- 
beate Spring .. .. ae 50s Anetyn OR 
Case of Hernia atll Yy “shail by an oaaiaen 214 
On the Action of the Vegetable Acids on Alcohol, with-or 
frithout the Intermedium of the Mineral Acids .. 216 
Extract from « Memoir on the Topography and the upper 
Strata (le Relief) of the Soil of Paris  .. .. 223 
Description of a portable Mineralogical Laboratory . 241 , 
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