f BOB 
§ 4. Both masses of tellurium mixed with 5—6 times the amount 
of powdered, freshly prepared potassium cyanide were fused for 
some hours in large Rose crucibles in an atmosphere of coal gas, 
with the aid of a large PERROT-furnace. In the course of a few 
months, about 5 kilos of these melts were obtained. When carefully 
powdered, the dark coloured masses dissolve in recently boiled, hot 
water to beautiful purple coloured solutions, which on cold oxidation 
by purified air deposit, from the K,Te all the tellurium in brilliant 
needles. On melting the masses, the poisonous influence of the hy¬ 
drogen telluride, which is formed in small quantities, was experienced 
only too plainly, also the disagreeable consequences of breathing the 
very small "quantities of TeCl a formed during the treatment with 
aqua regia. For weeks afterwards the breath has a powerful odour 
of (CH g ), Te, which resembles phosphine and is exceedingly sensitive 
to the olfactory nerve of bystanders . l ) 
The crystalline and. already very pure tellurium thus obtained is 
free from selenium as proved by the exceedingly delicate Norris 
potassiumiodide-reaotion and by the non-reduction of the TeO g by 
hydroxylamine in strong hydrochloric acid solution. All the selenium 
has been removed as KCNSe, whilst the tellurium has passed into 
K 2 Te and then has again been liberated by the action of air free 
from H 2 S. 
The purified element was now distilled in vacuo at about 600- 
700° in long tubes made of hard glass and containing plugs of 
asbestos: a Teclu furnace was used. This operation was repeated 
about seven times, each time about 10 grams were used. The pure 
tellurium' thus obtained was silvery white and coarsely crystalline, 
much resembling crystallised antimony. 
The determinations carried out have been made with the product 
obtained from telluric acid. The sulphur was recrystallised twice from 
boiling toluene and heated in a drying oven at 90° for some hours. 
i) The opinions as to the physiological actions of tellurium are still very much 
divided. Although selenium is an element hardly less poisonous than arsenic, tellu¬ 
rium is considered by Gzapek and Weill (Chem N (1893), 1098 2) to be com¬ 
paratively harmless, owing to the much more rapid reduction of the tellurium 
compounds and the consequent localisation in the organism. The experience gained 
in my laboratory proves this view to be incorrect. 
Tellurium is undoubtedly poisonous, but the individual sensitiveness to small 
traces varies widely with different persons. TeH», in particular, is a poison causing 
severe headache and vomiting ; other telluriumeompounds such as TeCb, for 
instance are supposed to cause much inconvenience only, owing to their conversion 
into malodorous substances, but still there can be no doubt whatever as to their 
poisonous nature. 
