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A condition called the zinc shakes or "zinc chills" can be induced by inhalation of zinc fumes while brazing or welding galvanized materials. [149] Zinc is a common ingredient of denture cream which may contain between 17 and 38 mg of zinc per gram. Disability and even deaths from excessive use of these products have been claimed. [246]
The balangay was the first wooden marine vessel ever excavated in Southeast Asia. It is also known as the Butuan boat, as nine specimens of these boats, dating back to pre-Hispanic times (the earliest being in 320 CE), were discovered in 1976, Butuan, Mindanao. It is believed that the Austronesians migrated to the Philippine archipelago, riding ...
Lavoisier writes the first modern list of chemical elements – containing 33 elements including light and heat but omitting Na, K (he was unsure of whether soda and potash without carbonic acid, i.e. Na 2 O and K 2 O, are simple substances or compounds like NH 3), [91] Sr, Te; some elements were listed in the table as unextracted "radicals ...
The chemical elements were discovered in identified minerals and with the help of the identified elements the mineral crystal structure could be described. One milestone was the discovery of the geometrical law of crystallization by René Just Haüy , a further development of the work by Nicolas Steno and Jean-Baptiste L. Romé de l'Isle (the ...
Sphalerite is an important ore of zinc; around 95% of all primary zinc is extracted from sphalerite ore. [42] However, due to its variable trace element content, sphalerite is also an important source of several other metals such as cadmium, [ 43 ] gallium, [ 44 ] germanium, [ 45 ] and indium [ 46 ] which replace zinc.
It is a local adaptation of the Hispanic tradition of carrying small light sources (like torches, candles, or braziers) during the nine-day Christmas Novena procession leading up to the midnight mass (called Simbang Gabi in the Philippines). [5] [9] [10]
Chlorine was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele, who called it "dephlogisticated marine acid" (see phlogiston theory) and mistakenly thought it contained oxygen. Scheele observed several properties of chlorine gas, such as its bleaching effect on litmus, its deadly effect on insects, its yellow-green colour, and the ...
The gas was first synthesised in 1772 by the natural philosopher and chemist Joseph Priestley, who called it dephlogisticated nitrous air (see phlogiston). [13] Priestley described his discovery in the book Experiments and Observations on Different Kinds of Air (1775) , in which he described how to produce the preparation of "nitrous air ...