Formation of Gold Kuggets. 57 



detected, even with the aid of the microscope, until nearly 

 all the pyrites has been oxidized and decomposed. In a few 

 exceptional cases pieces have been fonnd projecting, but all 

 tends to prove the priority of the deposition of the gold, and 

 that instead of pyrites having formed a nucleus for the gold, 

 the reverse has in the majority of instances been the case. 



It may also have been the first to deposit in the drift wood, 

 for in all the experiments by Mr. Wilkinson and myself the 

 organic structure became so impregnated with gold that when 

 ignited (so as to burn off the undecomposed organic matter) 

 a golden model remained. Flies, which fell into some of my 

 experiments, and were useful in keeping up a supply of 

 fresh organic matter, became so thoroughly impregnated 

 that in some cases the finest hairs on their backs and legs 

 were to be seen in bright gold after ignition. Conditions 

 such as these (before ignition) would be very favourable to 

 the formation of pyrites, offering to a ferruginous water 

 containing sulphates, a reducing agent and congenial nuclei 

 for the crystals to form on. Crystalline gold is very easily 

 made, by simply introducing a chip of wood into a solution 

 of chloride of gold, containing five or six per cent of the 

 salt. The crystals are first seen on the surface of the 

 liquid as a thin film, which, as it grows heavier, falls to the 

 bottom, where it assumes a moss-like appearance ; if this is 

 examined under the microscope, it will be found to be a 

 network of octahedral crystals resembling very closely 

 the gold crystals from pyrites. These crystals have been 

 repeatedly made, in a carefully closed vessel, so that no 

 dust might enter, and falling on the surface form 

 nuclei for them. With these crystals I sometimes found 

 irregular pieces of gold, some in places showing planes of 

 octahedrons. In these experiments, as in all the others, 

 organic matter is necessary, the action ceasing when it was 

 removed, starting again immediately with a fresh addition. 



These experiments are based on the assumption that the 

 gold exists in the pyrites on the metallic form, and not as 

 sulphide, as has been supposed to be the case by some. Mr. 

 Daintree got gold in solution by digesting some of the 

 pyrites from Clunes in sulphide of ammonium, but I have 

 always failed to prove the presence of it as negative evi- 

 dence against it. I have the result of experiments made 

 by digesting the pyrites with an oxidizing agent, washing 

 the residue free from impurties, weighing the gold and 

 comparing the result with that got from a portion of the 



