508 JOURNAL, BOMBAY NATURAL HISTORY SOCIETy, Vol. XIX, 



no preservative need be used, no paper is there to turn brown, the smooth 

 white surface shows up the insects splendidly and takes pins very well. It is 

 possible that in time the naphthalin will evaporate enough to spoil the surface 

 or that dust will accumulate on the paraffin. The relief of knowing that one's 

 specimens are absolutely secure against psocids, moulds and beetles, without 

 constant renewal of naphthalin is an enormous boon and we would recom- 

 mend that the box be given a trial. We have over 120 in use in the 

 reference collection, a large number more in daily use and at a later date 

 will give the Society the results of our further experience. 



Pins. — In our damp climate, a source of frequent damage to collections 

 is the corrosion of the pins, often with the formation of masses of green 

 matter. Steel pins rust, all pins we have used are liable to corrode and we 

 have found no pin that is immune to corrosion. This is due partly to "the 

 tin coating of the tins, partly to the fact of an alloy being used. 

 With a pure metal, uncoated with another metal, electrical action does 

 not stimulate chemical action. We approached a prominent firm of 

 pin-makers, with the results that pure nickel pins in a long thick size 

 (No. 16) and a fine size (No. Ill) are now available at little more 

 than the prices of ordinary , black pins and at far less than pure silver pins. 

 We would call the attention of workers in the tropics to these pins ; they 

 have not the elasticity of steel but they have a sufficient strength to stand 

 ordinary wear and tear and, using pith for small insects, a long thick pin and 

 a fine small one meet nearly all demands. We are inducing (he makers to 

 produce a double pointed fine pin, which can be pushed into a small insect 

 from below and then (the other end) pushed into pith, this greatly facilitating 

 the pinning of small insects. Such nickel pins, tested against all other pins, 

 have entirely resisted corrosion where the latter corroded. On the continent, 

 pure nickel pins are in use and can be purchased in continental sizes. So far 

 as our experience goes nickel pins are advisable, but we have not had them 

 under trial for a sufficiently long period. 



It will be seen that we have not worked on the principle of making air- 

 tight boxes for the very obvious reason that to use them you must (a) close 

 the boxes when the air is dry and not re-open it till the monsoon is over, or (&) 

 dry the air inside. The former is impossible, we cannot shut our collection 

 from May to November. The latter is impossible in practice. We have tried 

 calcium chloride and copper sulphate (calcined) in the boxes and abandoned 

 it ; it requires constant renewal if the boxes are opened at all, the calcium 

 chloride becomes liquid, spills in the box and that box must be cleared out 

 and remade as only soaking will take out the chloride. The subject is one of 

 immense importance in this country, it would be an immense loss if collections 

 like those of the late M. de Niceville were to perish, and if large reference 

 collections cannot be maintained it must always be difficult to work. Some 

 improvements are undoubtedly required, and we are still so apprehensive of 

 damage that we never retain types of new species in this country ; if new 



