456 Transactions. — Ch emistry. 



cent, of nickel is mined with lorofit ; while at Frieberg, in Saxony, even a 

 much lower percentage is thought well worth the expense of recovery. 



I cannot allow this short note to close without a few words upon a metal 

 frequently accompanying nickel : I allude to cobalt.* In the instances 

 which I have already mentioned I did not find a trace of this metal, though 

 I have succeeded in discovering it in this district in four distinct places in 

 the shape of asbolite, the highest percentage yet found being 2-42 per cent., 

 and this entirely free from nickel. I hope in the coming summer to still 

 further investigate these deposits and bring the matter again before the 

 Institute. With respect to the successful manipulation and refining of 

 these minerals for commercial purposes in New Zealand, I am afraid very 

 little can be done until we have sulphuric acid manufactured in the colony, 

 as the importation of this article entirely excludes all chances of successful 

 competition with the home refiners, and in consequence ores which might 

 be utilized with profit must lie idly by awaiting the time when, from the 

 cheap production of acid and its concomitant products, there may be a 

 possibilitj'' of extending our manufactures and utilizing some of the raw 

 material which the colony possesses. 



Art. LXX. — Notes on a Deposit in the Shaft of the Pumping Association. 



By G-. Black. 

 {Read before the Auckland Institute, 20th August, 1877.] 

 I EXHIBIT samples of the lime deposit which lately formed in the pumps 

 and upon the timbers of the United Pumping Association shaft ; the slab 

 was broken ofi' one of the timber frames in the shaft at a depth of 540 feet 

 from the surface. I will briefly give a few details of its mode of occurrence. 

 This incrustation was first observed when the shaft was about 530 feet 

 deep ; in sinking at that depth a large body of quartz had been cut through, 

 and when the strata upon which the quartz was lying was cut into, a great 

 change took place ; the water formerly was acidulous, it now became 

 alkaline, and it was highly charged with carbonate of lime, which it held in 

 solution and precipitated as it came in contact with the carbonic acid gas in 

 the shaft. This deposit formed remarkably fast, and did not continue 

 regular, some weeks it would form more in thickness than it did in others. 

 The average thickness it formed on the buckets of the pumps was about, a 

 quarter of an inch in a week; it would coat a pick handle or drill in twelve 

 hours, and this was a great source of annoyance to the men working in 

 the bottom of the shaft, as the pick and hammer handles got coated with 



