441- PHILOSOPHICAI. TRA.NSACTIONS. [aNNO I767. 



crease in some fish is surprizing, and to those that are not used to disquisitions 

 of this kind must appear incredible ; he however sinks the number of eggs in 

 these two species extremely, when he tells us the roe of a cod-fish must contain 

 about a million of eggs, and that a carp does not spawn less than 20,000 ; to 

 which he adds, and perhaps a tench half as many. This is making the cod al- 

 most 10 times less prolific than the other account, and the carp above 17 times 

 less. Some other writers, who appear also to have been desirous to impress the 

 mind with the wonders of natural history, have made their estimate still lower. 

 One of them, in particular, in one of our monthly publications, whence num- 

 bers n>ust take their ideas, who have no opportunity of reading more authentic 

 accounts elsewhere, tells us, that carp and perch have Q or 10 thousand eggs, 

 and that cod-fish, and herring, are not less prolific ; and this he calls wonderful. 

 The increase df cod-fish is indeed, even according to this, very great, but almost 

 1000 times less than Leuwenhoeck is said to have found it. 



Their accounts being so very different, Mr. H. thought he should not impro- 

 perly employ some leisure hours, if he inquired into this matter afresh, and saw 

 what the fecundity of these species of fish really was, as well as of such other 

 sorts as might fall in his way ; and especially as he had found that a small pic- 

 kerel, whose spawn he had taken a pretty exact account of, from mere curiosity, 

 some time before, contained no fewer than 25,800 eggs: a fish which none of 

 these authors had mentioned, and of which notwithstanding a small one had pro- 

 duced a larger number of eggs than Bradley himself had assigned to the carp, 

 which has been always considered as remarkable for its prolific quality, not to 

 mention the unknown writer, who makes its fecundity much less. 



Mr. H.'s way of research, was to weigh the whole spawn very exactly ; then to 

 t^ke a piece weighing 20, 30, or 40, or more grains, as was most convenient, 

 and after weighing that parcel with care, and giving the turn of the scales to the 

 weights, not to the eggs, to tell them over very carefully ; and then by dividing 

 the number of eggs by the grains, to find how many eggs there were in each 

 grain, or nearly so. He says nearly, for there must, according to this method, 

 have been rather more; but he chose to estimate them after 'this manner, that 

 there might be no danger of representing the fecundity of these animals greater 

 than the truth. He often boiled the portions of spawn that he told, and after 

 macerating them some hours in water, gently pressed them with a penknife, 

 whose point he afterwards made use of to immber them distinctly, by separating 

 them from each other to greater distances, after they were rendered by that 

 gentle squeezing fitter for telling over. The weights he reckoned by are Avoir- 

 dupois weights ; but there being no weights of that sort small enough to answer 

 all purposes, he was obliged to make use of grains along with them, of which 

 he reckoned 4374- make an ounce avoirdupois. 



The table, at the close, gives all particulars, in a very short compass. The first 



