5 
558 Transactions. —Chemistry. 
least as to their exterior parts, of aluminium, and, in consequence of this, to 
be incorrodible by ink of this kind. Large numbers of them had been sold 
by him to various Governments and private persons under these representa- 
tions; but, in an unpropitious hour, he was moved to attempt a sale of them 
to our Colonial Government, and under the same representations on their 
behalf as had been hitherto so successful. A sample of them was therefore 
handed for examination to the Department to which I belong, when their 
true character as steel pens was for the first time ascertained and publicly 
announced. 
The fact that there had been such a rush after pens supposed to be 
incorrodible, showed the great necessity there is for a cheap pen which is 
proof against the corrosive action of our common. writing inks, or of a good 
cheap writing ink which will not corrode our steel pens ; and I accordingly 
thought the matter over, when it occurred to me that the ink might at any 
rate be modified so as to afford us this great desideratum. The way in 
which such an ink should be modified for this purpose will at once suggest 
itself to you when the specific cause of its corrosive effect upon steel is con- 
sidered. This is, as you are aware, the combination of oxygen with the 
iron of the pen, and a partial solution of the compound thus formed in 
the acids (gallic, tannic, carbonic acid, etc.) of which the ink in part con- 
sists, the rest of the compound combining with these acids to form adherent 
flocks or lamins upon the pen. 
Now it is a well-known fact that all these processes—in short this 
corrosion, or indeed any corrosion of iron or steel—can only go on when 
the surrounding liquid is in an acid or possibly neutral condition ; at least 
to speak guardedly and in mind of the easy superficial oxidizement of even 
the noble metals which I have before this shown to you,* it can but go on 
to a very limited, indeed an imperceptible extent as regards vision. It 
will therefore occur to you, as it occurred to me, that by alkalizing our 
common ink, a product would be obtained having no visible effect upon 
steel pens, the only question to determine being this—whether we can so 
radically change the character of the ink without rendering it useless ? In 
regard to this question, I believe that I have, after several experiments, 
settled it quite favourably by using bi-carbonate of ammonia as the alka- 
lizing agent. Any other bi-carbonate will do too, as also borax, or alkaline 
phosphates ; but the first salt is on the whole the best, as any notable 
excess of it does not, on account of its volatility, long incommode one. 
Ammonia, or common soda, cannot safely be used for this purpose, as 
matters so caustic as these change the color of the ink to a weak pink or 
purple. 
* Vol, VIII. ** Trans. N-Z. Institute," p. 332. 
